This invention relates to diagnostic and/or therapeutically active agents, more particularly to diagnostic and/or therapeutically active agents incorporating moieties having affinity for sites and/or structures within the body so that diagnostic imaging and/or therapy of particular locations within the body may be enhanced. Of particular interest are diagnostic agents for use in ultrasound imaging, which are hereinafter referred to as targeted ultrasound contrast agents.
It is well known that ultrasonic imaging comprises a potentially valuable diagnostic tool, for example in studies of the vascular system, particularly in cardiography, and of tissue microvasculature. A variety of contrast agents has been proposed to enhance the acoustic images so obtained, including suspensions of solid particles, emulsified liquid droplets, gas bubbles and encapsulated gases or liquids. It is generally accepted that low density contrast agents which are easily compressible are particularly efficient in terms of the acoustic backscatter they generate, and considerable interest has therefore been shown in the preparation of gas-containing and gas-generating systems.
Gas-containing contrast media are also known to be effective in magnetic resonance (MR) imaging, e.g. as susceptibility contrast agents which will act to reduce MR signal intensity. Oxygen-containing contrast media also represent potentially useful paramagnetic MR contrast agents.
Furthermore, in the field of x-ray imaging it has been observed that gases such as carbon dioxide may be used as negative oral contrast agents or intravascular contrast agents.
The use of radioactive gases, e.g. radioactive isotopes of inert gases such as xenon, has also been proposed in scintigraphy, for example for blood pool imaging.
Targeted ultrasound contrast agents may be regarded as comprising (i) a reporter moiety capable of interacting with ultrasound irradiation to generate a detectable signal; (ii) one or more vectors having affinity for particular target sites and/or structures within the body, e.g. for specific cells or areas of pathology; and (iii) one or more linkers connecting said reporter and vector(s), in the event that these are not directly joined.
The molecules and/or structure to which the contrast agent is intended to bind will hereinafter be referred to as the target. In order to obtain specific imaging of a selected region/structure in the body the target must be present and available in this region/structure. Ideally it will be expressed only in the region of interest, but usually will also be present at other locations in the body, creating possible background problems. The target may either be a defined molecular species (i.e. a target molecule) or an unknown molecule or more complex structure (i.e. a target structure) which is present in the area to be imaged, and is able to bind specifically or selectively to a given vector molecule.
The vector is attached to the reporter moiety in order to bind these moieties to the region/structure to be imaged. The vector may bind specifically to a chosen target, or it may bind only selectively, having affinity also for a limited number of other molecules/structures, again creating possible background problems.
There is a limited body of prior art relating to targeted ultrasound contrast agents. Thus, for example, U.S. Pat. No. 5,531,980 is directed to systems in which the reporter comprises an aqueous suspension of air or gas microbubbles stabilised by one or more film-forming surfactants present at least partially in lamellar or laminar form, said surfactant(s) being bound to one or more vectors comprising xe2x80x9cbioactive species designed for specific targeting purposesxe2x80x9d. It is stated that the microbubbles are not directly encapsulated by surfactant material but rather that this is incorporated in liquid-filled liposomes which stabilise the microbubbles. It will be appreciated that lamellar or laminar surfactant material such as phospholipids present in such liposomes will inevitably be present in the form of one or more lipid bilayers with the lipophilic tails xe2x80x9cback-to-backxe2x80x9d and the hydrophilic heads both inside and outside (see e.g. Schneider, M. on xe2x80x9cLiposomes as drug carriers: 10 years of researchxe2x80x9d in Drug targeting, Nyon, Switzerland, Oct. 3-5, 1984, Buri, P. and Gumma, A. (Ed), Elsevier, Amsterdam 1984).
EP-A-0727225 describes targeted ultrasound contrast agents in which the reporter comprises a chemical having a sufficient vapour pressure such that a proportion of it is a gas at the body temperature of the subject. This chemical is associated with a surfactant or albumin carrier which includes a protein-, peptide- or carbohydrate-based cell adhesion molecule ligand as vector. The receptor moieties in such contrast agents correspond to the phase shift colloid systems described in WO-A-9416739; it is now recognised that administration of such phase shift colloids may lead to generation of microbubbles which grow uncontrollably, possibly to the extent where they cause potentially dangerous embolisation of, for example, the myocardial vasculature and brain (see e.g. Schwarz, Advances in Echo-Contrast [1994(3)], pp 48-49).
WO-A-9320802 proposes that tissue-specific ultrasonic image enhancement may be achieved using acoustically reflective oligolamellar liposomes conjugated to tissue-specific ligands such as antibodies, peptides, lectins etc. The liposomes are deliberately chosen to be devoid of gas and so will not have the advantageous echogenic properties of gas-based ultrasound contrast agents. Further references to this technology, e.g. in targeting to fibrin, thrombi and atherosclerotic areas are found in publications by Alkanonyuksel, H. et al. in J. Pharm. Sci. (1996) 85(5), 486-490; J. Am. Coll. Cardiol. (1996) 27(2) Suppl A, 298A; and Circulation, 68 Sci. Sessions, Anaheim Nov. 13-16, 1995.
There is also a number of publications concerning ultrasound contrast agents which refer in passing to possible use of monoclonal antibodies as vectors without giving significant practical detail and/or to reporters comprising materials which may be taken up by the reticuloendothelial system and thereby permit image enhancement of organs such as the liverxe2x80x94see, for example WO-A-9300933, WO-A-9401140, WO-A-9408627, WO-A-9428874, U.S. Pat. Nos. 5,088,499, 5,348,016 and 5,469,854. In general these prior art targeted contrast agents are intended to enhance contrast at specific sites in the body, for example tumour cells, by using one vector to bind strongly to one target, in order to achieve concentration at the target cells. In contrast to this principle of using one vector to bind with high affinity to one target, the present invention is based in part on the finding that diagnostic and/or therapeutically active agents with more favourable properties may be obtained by use of multiple kinds of vector-target interactions (e.g. involving agents associated with a plurality of different vectors and/or with one or more vectors having affinity for different targets on the same or different cell types). In this way, binding of gas-containing and gas-generating diagnostic and/or therapeutic agents may, for example, be obtained by forming multiple binding pairs between one vector with specificity for more than one receptor or between more than one vector with affinity for one or more types of target, with either low or high affinities. Such multiple binding of the vector-conjugated agent to one or more target molecules/structures may result in advantageous targeting properties, for example by enhancing target specificity and/or by distinguishing interactions at a desired target area from background interactions with lower levels of molecules/structures similar to target expressed elsewhere in the body.
It is well known to use one vector binding with high affinity to one target. The present invention, however, is based on the finding that the desired binding of gas-containing and gas-generating diagnostic and/or therapeutic agents may be obtained by forming multiple binding pairs with low affinity between one type of vector and one type of target, or by forming multiple binding pairs between one or more types of vectors and one or more types of target, with either low or high affinities. Thus multiple binding of the vector conjugated agent to one or more target molecules/structures may have advantageous targeting properties, for example in enhancing target specificity and/or in distinguishing interactions at a desired target area from background interactions with lower levels of molecules/structures similar to target expressed elsewhere in the body.
Thus according to one aspect of the present invention there is provided a targetable diagnostic and/or therapeutically active agent, e.g. an ultrasound contrast agent, comprising a suspension in an aqueous carrier liquid, e.g. an injectable carrier liquid, of a reporter comprising gas-containing or gas-generating material characterised in that said agent is capable of forming at least two types of binding pairs, e.g. being conjugated to at least two vectors or to one vector capable of binding to at least two binding sites.
One advantageous embodiment of the invention is based on the additional finding that limited adhesion to targets is a highly useful property of diagnostic and/or therapeutically active agents, which property may be achieved using vectors giving temporary retention rather than fixed adhesion to a target. Thus such agents, rather than being fixedly retained at specific sites, may for example effectively exhibit a form of retarded flow along the vascular endothelium by virtue of their transient interactions with endothelial cells. Such agents may thus become concentrated on the walls of blood vessels, in the case of ultrasound contrast agents providing enhanced echogenicity thereof relative to the bulk of the bloodstream, which is devoid of anatomical features. They therefore may permit enhanced imaging of the capillary system, including the microvasculature, and so may facilitate distinction between normal and inadequately perfused tissue, e.g. in the heart, and may also be useful in visualising structures such as Kupffer cells, thrombi and atherosclerotic lesions or for visualising neo-vascularized and inflamed tissue areas. The present invention is well suited to imaging changes occurring in normal blood vessels which are situated in areas of tissue necrosis.
It will be appreciated that binding affinities are dependent on numbers of interactions as well as their strength. The density of vector molecules at the surface of the reporter units may therefore be selected so as appropriately to adjust the degree of interactions between particular agents and targets.
The term multiple-specificity is also used to describe an injectable carrier liquid, of gas-containing or gas-generating material composed of one or more vectors with a specificity for one or more cellular surface receptors while at the same time comprising a second element with specificity for a substrate or receptor system binding to which induces a therapeutic response. Thus included within the scope of the present invention are multiple-specific imaging agents comprising a targeting vector, such as the anti-fibrin antibody described by Lanza et al. (Circulation, (1996) 94 (12),pp 3334), annexin V atherosclerotic plaque binding peptides such as YRALVDTLK, or any other vector known to associate with fibrin clots, in combination with a drug or enzyme with fibrinolytic activity such as streptokinase, plasminogen activator (tPA), urokinase (uPA) or prourokinase (scuPA) resulting in a localised therapeutic antithrombotic effect. This invention is also extended to include vectors with increased specificity for tumour cells in combination with vectors or drug molecules functioning as chemotherapeutic agents capable of inhibiting tumour growth.
It is well known that many, if not all, target molecules are not expressed exclusively at target sites; a common situation is that such molecules are over-expressed by target cells or at a target structure but are also expressed at lower levels elsewhere in the body. The use of reporters carrying a multiplicity of vectors with relatively low affinity for the target may be advantageous in this situation, since the reporter will then tend to concentrate in regions of high target density which permit multiple (and therefore strong) binding to the reporter (e.g. a gas-containing agent incorporating the vectors folic acid and glutathione for multiple-specific binding to folic acid receptors and glutathione-S-trasferase receptors respectively which are over-expressed as tumour cells). Areas of low target density, on the other hand, will not provide sufficient interaction with such low affinity vectors to bind the target. In such embodiments of the invention, low affinity vectors may be regarded as having an association constant Ka for interaction with a target molecule or structure of less than 108 Mxe2x88x921, e.g. less than 107 Mxe2x88x921, preferably less than 106 Mxe2x88x921. A further embodiment of this invention is thus based on the finding that the desired binding of gas-containing and gas-generating diagnostic and/or therapeutic agents may be obtained by forming binding pairs with low affinity between more than one type of vector and one or more type of target. Multiple vectors may therefore be used to increase specificity, so that the reporter will bind only to target cells or structures expressing a particular combination of target molecules.
It may also be useful to select a plurality of vectors which bind to different parts, e.g. epitopes, of a target structure in order to give increased binding strength. This may be particularly advantageous when the target density is low.
Products comprising two or more vectors with different specificities, i.e. which bind to different target molecules on different cells, may advantageously be used as xe2x80x9cgeneral purposexe2x80x9d agents for detection of a range of diseases, e.g. different forms of cancer. Thus, for example, the use of such agents may enable detection of metastases, which are often heterogeneous with respect to expression of target molecules (i.e. antigens).
Within the context of the present invention, the reporter unit will usually remain attached to the vectors. In another type of targeting procedure, sometimes called pre-targeting, the vector (often, a monoclonal antibody) is administered alone; subsequently, the reporter is administered, coupled to a moiety which is capable of specifically binding the vector molecule (when the vector is an antibody, the reporter may be coupled to an immunoglobulin-binding molecule, such as protein A or an anti-immunoglobulin antibody). An advantage of this protocol is that time may be allowed for elimination of the vector molecules that do not bind their targets, substantially reducing the background problems that are connected with the presence of an excess of reporter-vector conjugate. Within the context of the present invention, pre-targeting with one specific vector might be envisaged, followed by reporter units that are coupled to another vector and a moiety which binds the first vector.
Within the context of the present invention, in some cases and in particular for the assessment of blood perfusion rates in defined areas, for example in myocardium, it is of interest to measure the rate at which ultrasound contrast agents bound to the target are displaced or released from the target. This can be achieved in a controlled fashion by subsequent administration of a vector or other agent able to displace or release the contrast agent from the target.
Vectors useful in accordance with the invention include ligands for cell adhesion proteins, as well as cell adhesion proteins themselves where these have corresponding ligands on endothelial cell surfaces. Examples of cell adhesion proteins include integrins, most of which bind the Arg-Gly-Asp (RGD) amino acid sequence. If desired, the vector may be targeted to specific cell adhesion proteins expressed mainly on activated endothelial cells such as are found at or close to sites of inflammation or other pathological responses. Other vectors which may be used include proteins and peptides that bind to cell-surface proteoglycans, which are complexes of proteins and sulphated polysaccarides found on most cells, including endothelial cells. Such proteoglycans contribute to the negative surface charge of all nucleated cells from vertebrate animals; this charge may also be exploited in accordance with the invention by using positively charged vectors, e.g. comprising cationic lipids, which will interact electrostatically with the endothelial surface.
A further aspect of the present invention is for example where a vector or vectors is attached to the reporter or included non-covalently into the reporter in a manner where the said vector or vectors is not readily exposed to the targets or receptors. Increased tissue specificity may therefore be achieved by applying an additional process to expose the vectors, e.g. the agent is exposed after administration to external ultrasound to change the diffusibility of the moieties containing the vectors.
The reporter may be in any convenient form, for example being any appropriate gas-containing or gas-generating ultrasound contrast agent formulation. Representative examples of such formulations include microbubbles of gas stabilised (e.g. at least partially encapsulated) by a coalescence-resistant surface membrane (for example gelatin, e.g. as described in WO-A-8002365), a filmogenic protein (for example an albumin such as human serum albumin, e.g. as described in U.S. Pat. Nos. 4,718,433, 4,774,958, 4,844,882, EP-A-0359246, WO-A-9112823, WO-A-9205806, WO-A-9217213, WO-A-9406477 or WO-A-9501187), a polymer material (for example a synthetic biodegradable polymer as described in EP-A-0398935, an elastic interfacial synthetic polymer membrane as described in EP-A-0458745, a microparticulate biodegradable polyaldehyde as described in EP-A-0441468, a microparticulate N-dicarboxylic acid derivative of a polyamino acid-polycyclic imide as described in EP-A-0458079, or a biodegradable polymer as described in WO-A-9317718 or WO-A-9607434), a non-polymeric and non-polymerisable wall-forming material (for example as described in WO-A-9521631), or a surfactant (for example a polyoxyethylene-polyoxypropylene block copolymer surfactant such as a Pluronic, a polymer surfactant as described in WO-A-9506518, or a film-forming surfactant such as a phospholipid, e.g. as described in WO-A-9211873, WO-A-9217212, WO-A-9222247, WO-A-9428780 or WO-A-9503835).
Other useful gas-containing contrast agent formulations include gas-containing solid systems, for example microparticles (especially aggregates of microparticles) having gas contained therewithin or otherwise associated therewith (for example being adsorbed on the surface thereof and/or contained within voids, cavities or pores therein, e.g. as described in EP-A-0122624, EP-A-0123235, EP-A-0365467, WO-A-9221382, WO-A-9300930, WO-A-9313802, WO-A-9313808 or WO-A-9313809). It will be appreciated that the echogenicity of such microparticulate contrast agents may derive directly from the contained/associated gas and/or from gas (e.g. microbubbles) liberated from the solid material (e.g. upon dissolution of the microparticulate structure).
The disclosures of all of the above-described documents relating to gas-containing contrast agent formulations are incorporated herein by reference.
Gas microbubbles and other gas-containing materials such as microparticles preferably have an initial average size not exceeding 10 xcexcm (e.g. of 7 xcexcm or less) in order to permit their free passage through the pulmonary system following administration, e.g. by intravenous injection.
Where phospholipid-containing compositions are employed in accordance with the invention, e.g. in the form of phospholipid-stabilised gas microbubbles, representative examples of useful phospholipids include lecithins (i.e. phosphatidylcholines), for example natural lecithins such as egg yolk lecithin or soya bean lecithin and synthetic or semisynthetic lecithins such as dimyristoylphosphatidylcholine, dipalmitoylphosphatidylcholine or distearoylphosphatidylcholine; phosphatidic acids; phosphatidylethanolamines; phosphatidylserines; phosphatidylglycerols; phosphatidylinositols; cardiolipins; sphingomyelins; fluorinated analogues of any of the foregoing; mixtures of any of the foregoing and mixtures with other lipids such as cholesterol. The use of phospholipids predominantly (e.g. at least 75%) comprising molecules individually bearing net overall charge, e.g. negative charge, for example as in naturally occurring (e.g. soya bean or egg yolk derived), semisynthetic (e.g. partially or fully hydrogenated) and synthetic phosphatidylserines, phosphatidylglycerols, phosphatidylinositols, phosphatidic acids and/or cardiolipins, may be particularly advantageous.
Other exemplary lipids which may be used to prepare gas-containing contrast agents include fatty acids, stearic acid, palmitic acid, 2-n-hexadecylstearic acid, oleic acid and other acid containing lipid structures. These lipid structures are considered particularly interesting when coupled by amide bond formation to amino acids containing one or more amino groups. The resulting lipid modified amino acids (e.g. dipalmitoyllysine, distearoyl-2,3-diaminopropionic acid) are considered useful precursors for the attachment of functionalised spacer elements featuring coupling sites for conjugation of one or more vector molecules.
A further extension of this invention relates to the synthesis of lipopeptide structures comprising a lipid reporter attached to a linker portion (e.g. PEG, polyamino acid, alkylhalide etc) the said linker being suitably functionalised for coupling to one or more vector molecules. A particular preference is the inclusion of a positively charged linker element (eg. two or more lysine residues) for anchoring of the reporter element in the microbubble through electrostatic interaction with the negatively charged membrane. Multiple-specific targeting is achievable by mixing and xe2x80x98dopingxe2x80x99 of phospholipid gas-containing structures with one or more targeted lipopeptide sequences. Multiple-specificity can also be achieved by assembling more than one vector on a branched lysine core structure such as those described by Tam et. al. (Proc. Natl. Acad. Sci. USA, 1989, 86, 9084) or by incorporating multiple vectors in a linear sequence. Multiple-specificity can also be achieved using lipopeptides or phospholipids comprising combinatorial libraries synthesised by chemical synthesis as described by Lowe (Combinatorial Chemistry, Chemical Society Reviews, 1995, 309-317).
Also within the scope of this invention are functionalised microbubbles carrying one or more reactive groups for non-specific reaction with receptor molecules located on cell surfaces. Microbubbles comprising a thiol moiety,for example, can bind to cell surface receptors via disulphide exchange reactions. The reversible nature of this covalent bond means that bubble flow can be controlled by altering the redox environment. Similarly xe2x80x98activatedxe2x80x99 microbubbles of membranes comprising active esters such as N-hydroxysuccinimide esters can be used to modify amino groups found on a multiplicity of cell surface molecules.
Representative examples of gas-containing microparticulate materials which may be useful in accordance with the invention include carbohydrates (for example hexoses such as glucose, fructose or galactose; disaccharides such as sucrose, lactose or maltose; pentoses such as arabinose, xylose or ribose; xcex1-, xcex2- and xcex3-cyclodextrins; polysaccharides such as starch, hydroxyethyl starch, amylose, amylopectin, glycogen, inulin, pulullan, dextran, carboxymethyl dextran, dextran phosphate, ketodextran, aminoethyldextran, alginates, chitin, chitosan, hyaluronic acid or heparin; and sugar alcohols, including alditols such as mannitol or sorbitol), inorganic salts (e.g. sodium chloride), organic salts (e.g. sodium citrate, sodium acetate or sodium tartrate), X-ray contrast agents (e.g. any of the commercially available carboxylic acid and non-ionic amide contrast agents typically containing at least one 2,4,6-triiodophenyl group having substituents such as carboxyl, carbamoyl, N-alkylcarbamoyl, N-hydroxyalkylcarbamoyl, acylamino, N-alkylacylamino or acylaminomethyl at the 3- and/or 5-positions, as in metrizoic acid, diatrizoic acid, iothalamic acid, ioxaglic acid, iohexol, iopentol, iopamidol, iodixanol, iopromide, metrizamide, iodipamide, meglumine iodipamide, meglumine acetrizoate and meglumine diatrizoate), and polypeptides and proteins (e.g. gelatin or albumin such as human serum albumin).
Any biocompatible gas may be present in the reporter of contrast agents according to the invention, the term xe2x80x9cgasxe2x80x9d as used herein including any substances (including mixtures) substantially or completely in gaseous (including vapour) form at the normal human body temperature of 37xc2x0 C. The gas may thus, for example, comprise air; nitrogen; oxygen; carbon dioxide; hydrogen; an inert gas such as helium, argon, xenon or krypton; a sulphur fluoride such as sulphur hexafluoride, disulphur decafluoride or trifluoromethylsulphur pentafluoride; selenium hexafluoride; an optionally halogenated silane such as methylsilane or dimethylsilane; a low molecular weight hydrocarbon (e.g. containing up to 7 carbon atoms), for example an alkane such as methane, ethane, a propane, a butane or a pentane, a cycloalkane such as cyclopropane, cyclobutane or cyclopentane, an alkene such as ethylene, propene, propadiene or a butene, or an alkyne such as acetylene or propyne; an ether such as dimethyl ether; a ketone; an ester; a halogenated low molecular weight hydrocarbon (erg. containing up to 7 carbon atoms); or a mixture of any of the foregoing. Advantageously at least some of the halogen atoms in halogenated gases are fluorine atoms; thus biocompatible halogenated hydrocarbon gases may, for example, be selected from bromochlorodifluoromethane, chlorodifluoromethane, dichlorodifluoromethane, bromotrifluoromethane, chlorotrifluoromethane, chloropentafluoroethane, dichlorotetrafluoroethane, chlorotrifluoroethylene, fluoroethylene, ethylfluoride, 1,1-difluoroethane and perfluorocarbons, e.g. perfluoroalkanes such as perfluoromethane, perfluoroethane, perfluoropropanes, perfluorobutanes (e.g. perfluoro-n-butane, optionally in admixture with other isomers such as perfluoro-iso-butane), perfluoropentanes, perfluorohexanes and perfluoroheptanes; perfluoroalkenes such as perfluoropropene, perfluorobutenes (e.g. perfluorobut-2-ene) and perfluorobutadiene; perfluoroalkynes such as perfluorobut-2-yne; and perfluorocycloalkanes such as perfluorocyclobutane, perfluoromethylcyclobutane, perfluorodimethylcyclobutanes, perfluorotrimethylcyclobutanes, perfluorocyclopentane, perfluoromethylcyclopentane, perfluorodimethylcyclopentanes, perfluorocyclohexane, perfluoromethylcyclohexane and perfluorocycloheptane. Other halogenated gases include methyl chloride, fluorinated (e.g. perfluorinated) ketones such as perfluoroacetone and fluorinated (e.g. perfluorinated) ethers such as perfluorodiethyl ether. The use of perfluorinated gases, for example sulphur hexafluoride and perfluorocarbons such as perfluoropropane, perfluorobutanes and perfluoropentanes, may be particularly advantageous in view of the recognised high stability in the bloodstream of microbubbles containing such gases.
The reporter may be made by any convenient process, for example by making gas-containing or gas-generating formulations. Representative examples include the preparation of a suspension of gas microbubbles by contacting a surfactant with gas and mixing them in the presence of an aqueous carrier, as described in WO 9115244; or by atomising a solution or dispersion of a wall-forming material in the presence of a gas in order to obtain hollow microcapsules, as described in EP 512693A1; preparation of solid microspheres by a double emulsion process, as described in U.S. Pat. No. 5,648,095; or a process for forming hollow microcapsules by spray-drying as described in EP 681843A2; or preparing gas-filled liposomes by shaking an aqueous solution comprising a lipid in the presence of a gas as described in U.S. Pat. No. 5,469,854.
A suitable process for attachment of the desired vector to the reporter comprises a surface modification of the preformed reporter with a suitable linker employing reactive groups on the surface of both the reporter and vector. It may be particularly advantageous physically to mix the reporter material with the vector-containing substance at any step of the process. Such a process will result in incorporation or an attachment of the vector to the reporter. An optional process step may remove the excess of vector not bound to the reporter by washing the gas-containing particles following separation, by for example, floatation. A preferred aspect is the use of lipopeptide structures incorporating functional groups such as thiol, maleimide biotin etc. which can be premixed if desired with other reporter molecules before formation of gas-containing agents. The attachment of vector molecules may be carried out using the linker reagents listed below.
Linking of a reporter unit to the desired vectors may be achieved by covalent or non-covalent means, usually involving interaction with one or more functional groups located on the reporter and/or vectors. Examples of chemically reactive functional groups which may be employed for this purpose include amino, hydroxyl, sulfhydryl, carboxyl, and carbonyl groups, as well as carbohydrate groups, vicinal diols, thioethers, 2-aminoalcohols, 2-aminothiols, guanidinyl, imidazolyl and phenolic groups.
Covalent coupling of reporter and vectors may therefore be effected using linking agents containing reactive moieties capable of reaction with such functional groups. Examples of reactive moieties capable of reaction with sulfhydryl groups include xcex1-haloacetyl compounds of the type Xxe2x80x94CH2COxe2x80x94 (where Xxe2x95x90Br, Cl or I), which show particular reactivity for sulfhydryl groups but which can also be used to modify imidazolyl, thioether, phenol and amino groups as described by Gurd, F. R. N. in Methods Enzymol. (1967) 11, 532. N-Maleimide derivatives are also considered selective towards sulfhydryl groups, but may additionally be useful in coupling to amino groups under certain conditions. N-maleimides may be incorporated into linking systems for reporter-vector conjugation as described by Kitagawa, T. et al. in Chem. Pharm. Bull. (1981) 29, 1130 or used as polymer crosslinkers for bubble stabilisation as described by Kovacic, P. et al. in J. Am. Chem. Soc. (1959) 81, 1887. Reagents such as 2-iminothiolane, e.g. as described by Traut, R. et al. in Biochemistry (1973) 12, 3266, which introduce a thiol group through conversion of an amino group, may be considered as sulfhydryl reagents if linking occurs through the formation of disulphide bridges. Thus reagents which introduce reactive disulphide bonds into either the reporter or the vectors may be useful, since linking may be brought about by disulphide exchange between the vector and reporter; examples of such reagents include Ellman""s reagent (DTNB), 4,4xe2x80x2-dithiodipyridine, methyl-3-nitro-2-pyridyl disulphide and methyl-2-pyridyl disulphide (described by Kimura, T. et al. in Analyt. Biochem. (1982) 122, 271).
Examples of reactive moieties capable of reaction with amino groups include alkylating and acylating agents. Representative alkylating agents include:
i) xcex1-haloacetyl compounds, which show specificity towards amino groups in the absence of reactive thiol groups and are of the type Xxe2x80x94CH2COxe2x80x94 (where Xxe2x95x90Cl, Br or I), e.g. as described by Wong, Y-H. H. in Biochemistry (1979) 24, 5337;
ii) N-maleimide derivatives, which may react with amino groups either through a Michael type reaction or through acylation by addition to the ring carbonyl group as described by Smyth, D. G. et al. in J. Am. Chem. Soc. (1960) 82, 4600 and Biochem. J. (1964) 91, 589;
iii) aryl halides such as reactive nitrohaloaromatic compounds;
iv) alkyl halides as described by McKenzie, J. A. et al. in J. Protein Chem. (1988) 7, 581;
v) aldehydes and ketones capable of Schiff""s base formation with amino groups, the adducts formed usually being stabilised through reduction to give a stable amine;
vi) epoxide derivatives such as epichlorohydrin and bisoxiranes,which may react with amino, sulfhydryl or phenolic hydroxyl groups;
vii) chlorine-containing derivatives of s-triazines, which are very reactive towards nucleophiles such as amino, sufhydryl and hydroxy groups;
viii) aziridines based on s-triazine compounds detailed above, e.g. as described by Ross, W. C. J. in Adv. Cancer Res. (1954) 2, 1, which react with nucleophiles such as amino groups by ring opening;
ix) squaric acid diethyl esters as described by Tietze, L. F. in Chem. Ber. (1991) 124, 1215; and
x) xcex1-haloalkyl ethers, which are more reactive alkylating agents than normal alkyl halides because of the activation caused by the ether oxygen atom, e.g. as described by Benneche, T. et al. in Eur. J. Med. Chem. (1993) 28, 463.
Representative amino-reactive acylating agents include:
i) isocyanates and isothiocyanates, particularly aromatic derivatives, Which form stable urea and thiourea derivatives respectively and have been used for protein crosslinking as described by Schick, A. F. et al. in J. Biol. Chem. (1961) 236, 2477;
ii) sulfonyl chlorides, which have been described by Herzig, D. J. et al. in Biopolymers (1964) 2, 349 and which may be useful for the introduction of a fluorescent reporter group into the linker;
iii) Acid halides;
iv) Active esters such as nitrophenylesters or N-hydroxysuccinimidyl esters;
v) acid anhydrides such as mixed, symmetrical or N-carboxyanhydrides;
vi) other useful reagents for amide bond formation as described by Bodansky, M. et al. in xe2x80x98Principles of Peptide Synthesisxe2x80x99 (1984) Springer-Verlag;
vii) acylazides, e.g. wherein the azide group is generated from a preformed hydrazide derivative using sodium nitrite, e.g. as described by Wetz, K. et al. in Anal. Biochem. (1974) 58, 347;
viii) azlactones attached to polymers such as bis-acrylamide, e.g. as described by Rasmussen, J. K. in Reactive Polymers (1991) 16, 199; and
ix) Imidoesters, which form stable amidines on reaction with amino groups, e.g. as described by Hunter, M. J. and Ludwig, M. L. in J. Am. Chem. Soc. (1962) 84, 3491.
Carbonyl groups such as aldehyde functions may be reacted with weak protein bases at a pH such that nucleophilic protein side-chain functions are protonated. Weak bases include 1,2-aminothiols such as those found in N-terminal cysteine residues, which selectively form stable 5-membered thiazolidine rings with aldehyde groups, e.g. as described by Ratner, S. et al. in J. Am. Chem. Soc. (1937) 59, 200. Other weak bases such as phenyl hydrazones may be used, e.g. as described by Heitzman, H. et al. in Proc. Natl. Acad. Sci. USA (1974) 71, 3537.
Aldehydes and ketones may also be reacted with amines to form Schiff""s bases, which may advantageously be stabilised through reductive amination. Alkoxylamino moieties readily react with ketones and aldehydes to produce stable alkoxamines, e.g. as described by Webb, R. et al. in Bioconjugate Chem. (1990) 1, 96.
Examples of reactive moieties capable of reaction with carboxyl groups include diazo compounds such as diazoacetate esters and diazoacetamides, which react with high specificity to generate ester groups, e.g. as described by Herriot R. M. in Adv. Protein Chem. (1947) 3, 169. Carboxylic acid modifying reagents such as carbodiimides, which react through O-acylurea formation followed by amide bond formation, may also usefully be employed; linking may be facilitated through addition of an amine or may result in direct vector-receptor coupling. Useful water soluble carbodiimides include 1-cyclohexyl-3-(2-morpholinyl-4-ethyl)carbodiimide (CMC) and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC), e.g. as described by Zot, H. G. and Puett, D. in J. Biol. Chem. (1989) 264, 15552. Other useful carboxylic acid modifying reagents include isoxazolium derivatives such as Woodwards reagent K; chloroformates such as p-nitrophenylchloroformate; carbonyldiimidazoles such as 1,1xe2x80x2-carbonyldiimidazole; and N-carbalkoxydihydroquinolines such as N-(ethoxycarbonyl)-2-ethoxy-1,2-dihydroquinoline.
Other potentially useful reactive moieties include vicinal diones such as p-phenylenediglyoxal, which may be used to react with guanidinyl groups, e.g. as described by Wagner et al. in Nucleic acid Res. (1978) 5, 4065; and diazonium salts, which may undergo electrophilic substitution reactions, e.g. as described by Ishizaka, K. and Ishizaka T. in J. Immunol. (1960) 85, 163. Bis-diazonium compounds are readily prepared by treatment of aryl diamines with sodium nitrite in acidic solutions. It will be appreciated that functional groups in the reporter and/or vector may if desired be converted to other functional groups prior to reaction, e.g. to confer additional reactivity or selectivity. Examples of methods useful for this purpose include conversion of amines to carboxylic acids using reagents such as dicarboxylic anhydrides; conversion of amines to thiols using reagents such as N-acetylhomocysteine thiolactone, S-acetylmercaptosuccinic anhydride, 2-iminothiolane or thiol-containing succinimidyl derivatives; conversion of thiols to carboxylic acids using reagents such as xcex1-haloacetates; conversion of thiols to amines using reagents such as ethylenimine or 2-bromoethylamine; conversion of carboxylic acids to amines using reagents such as carbodiimides followed by diamines; and conversion of alcohols to thiols using reagents such as tosyl chloride followed by transesterification with thioacetate and hydrolysis to the thiol with sodium acetate.
Vector-receptor coupling may also be effected using enzymes as zero-length crosslinking agents; thus, for example, transglutaminase, peroxidase and xanthine oxidase have been used to produce crosslinked products. Reverse proteolysis may also be used for crosslinking through amide bond formation.
Non-covalent vector-receptor coupling may, for example, be effected by electrostatic charge interactions e.g. between a polylysinyl-functionalised reporter and a polyglutamyl-functionalised vector, through chelation in the form of stable metal complexes or through high affinity binding interaction such as avidin/biotin binding. Polylysine, coated non-covalently to the negatively charged membrane surface can also increase non-specifically the affinity of a microbubble for a cell through charge interactions.
Alternatively, vectors may be coupled to a protein or peptide sequence known to bind phospholipids. In many instances, a single molecule of phospholipid may attach to a protein such as a translocase, while other proteins may attach to surfaces consisting mainly of phospholipid head groups and so may be used to attach vectors to phospholipid microspheres; one example of such a protein is xcex22-glycoprotein I (Chonn, A., Semple, S.C. and Cullis, P. R., Journal of Biological Chemistry (1995) 270, 25845-25849). Phosphatidylserine-binding proteins have been described, e.g. by Igarashi, K. et al. in Journal of Biological Chemistry 270(49), 29075-29078. Annexins are a class of phospholipid-binding proteins, many of which bind particularly avidly to phosphatidyl-serine (reviewed in Raynal, P. and H. B. Pollard. Annexins: the problem of assessing the biological role for a gene family of multifunctional calcium- and phospholipid-binding proteinsxe2x80x9d. Biochim. Biophys. Acta 1197: 63-93). A conjugate of a vector with such a phosphatidylserine-binding protein may therefore be used to attach the vector to phosphatidylserine-encapsulated microbubbles. When the amino acid sequence of a binding protein is known, the phospholipid-binding portion may be synthesised or isolated and used for conjugation with a vector, thus avoiding the biological activity which may be located elsewhere in the molecule.
It is also possible to obtain molecules that bind specifically to the surface (or in the xe2x80x9cmembranexe2x80x9d) of microspheres by direct screening of molecular libraries for microsphere-binding molecules. For example, phage libraries displaying small peptides could be used for such selection. The selection may be made by simply mixing the microspheres and the phage display library and eluting the phages binding to the floating microspheres. If desired, the selection can be done under xe2x80x9cphysiological conditionsxe2x80x9d (e.g. in blood) to eliminate peptides which cross-react with blood components. An advantage of this type of selection procedure is that only binding molecules that do not destabilize the microspheres should be selected, since only binding molecules attached to intact floating microspheres will rise to the top. It may also be possible to introduce some kind of xe2x80x9cstressxe2x80x9d during the selection procedure (e.g. pressure) to ensure that destabilizing binding moieties are not selected. Furthermore the selection could be done under shear conditions e.g. by first letting the phages react with the microspheres and then letting the microspheres pass through a surface coated with anti-phage antibodies under flow conditions. In this way it may be possible to select binders which may resist shear conditions present in vivo. Binding moieties identified in this way may be coupled (chemically via peptide synthesis, or at the DNA-level using recombinant vectors) to a vector molecule, constituting a general tool for attaching any vector molecule to the microspheres.
A vector which comprises or is coupled to a peptide or lipopeptide linker which contains a element capable of mediating membrane insertion may also be useful. One example is described by Leenhouts, J. M. et al. in Febs Letters (1995) 370(3), 189-192. Non-bioactive molecules consisting of known membrane insertion anchor/signal groups may also be used as vectors for certain applications, an example being the H1 hydrophobic segment from the Na,K-ATPase xcex1-subunit described by Xie, Y. and Morimoto, T. in J. Biol. Chem. (1995) 270(20), 11985-11991. The anchor group may also be fatty acid(s) or cholesterol.
Coupling may also be effected using avidin or streptavidin, which have four high affinity binding sites for biotin. Avidin may therefore be used to conjugate vector to reporter if both vector and reporter are biotinylated. Examples are described by Bayer, E. A. and Wilchek, M. in Methods Biochem. Anal. (1980) 26, 1. This method may also be extended to include linking of reporter to reporter, a process which may encourage bubble association and consequent potentially increased echogenicity.
Non-covalent coupling may also utilise the bifunctional nature of bispecific immunoglobulins. These molecules can specifically bind two antigens, thus linking them. For example, either bispecific IgG or chemically engineered bispecific F(ab)xe2x80x22 fragments may be used as linking agents. Heterobifunctional bispecific antibodies have also been reported for linking two different antigens, e.g. as described by Bode, C. et al. in J. Biol. Chem. (1989) 264, 944 and by Staerz, U. D. et al. in Proc. Natl. Acad. Sci. USA (1986) 83, 1453. Similarly, any reporter and/or vector containing two or more antigenic determinants (e.g. as described by Chen, Aa et al. in Am. J. Pathol. (1988) 130, 216) may crosslink antibody molecules and lead to formation of multi-bubble cross-linked assemblies of potentially increased echogenicity.
So-called zero-length linking agents, which induce direct covalent joining of two reactive chemical groups without introducing additional linking material (e.g. as in amide bond formation induced using carbodiimides or enzymatically) may, if desired, be used, as may agents such as biotin/avidin systems which induce non-covalent reporter-vector linking and agents which induce hydrophobic or electrostatic interactions.
Most commonly, however, the linking agent will comprise two or more reactive moieties, e.g. as described above, connected by a spacer element. The presence of such a spacer permits bifunctional linkers to react with specific functional groups within a molecule or between two different molecules, resulting in a bond between these two components and introducing extrinsic linker-derived material into the reporter-vector conjugate. The reactive moieties in a linking agent may be the same (homobifunctional agents) or different (heterobifunctional agents or, where several dissimilar reactive moieties are present, heteromultifunctional agents), providing a diversity of potential reagents that may bring about covalent bonding between any chemical species, either intramolecularly or intermolecularly.
The nature of extrinsic material introduced by the linking agent may have a critical bearing on the targeting ability and general stability of the ultimate product. Thus it may be desirable to introduce labile linkages, e.g. containing spacer arms which are biodegradable or chemically sensitive or which incorporate enzymatic cleavage sites. Alternatively the spacer may include polymeric components, e.g. to act as surfactants and enhance bubble stability. The spacer may also contain reactive moieties, e.g. as described above to enhance surface crosslinking, or it may contain a tracer element such as a fluorescent probe, spin label or radioactive material.
Spacer elements may typically consist of aliphatic chains which effectively separate the reactive moieties of the linker by distances of between 5 and 30 xc3x85. They may also comprise macromolecular structures such as polytethylene glycols). Such polymeric structures, hereinafter referred to as PEGs, are simple, neutral polyethers which have been given much attention in biotechnical and biomedical applications (see e.g. Milton Harris, J. (ed) xe2x80x9cPoly(ethylene glycol) chemistry, biotechnical and biomedical applicationsxe2x80x9d Plenum Press, New York, 1992). PEGs are soluble in most solvents, including water, and are highly hydrated in aqueous environments, with two or three water molecules bound to each ethylene glycol segment; this has the effect of preventing adsorption either of other polymers or of proteins onto PEG-modified surfaces. PEGs are known to be nontoxic and not to harm active proteins or cells, whilst covalently linked PEGs are known to be non-immunogenic and non-antigenic. Furthermore, PEGs may readily be modified and bound to other molecules with only little effect on their chemistry. Their advantageous solubility and biological properties are apparent from the many possible uses of PEGs and copolymers thereof, including block copolymers such as PEG-polyurethanes and PEG-polypropylenes.
Appropriate molecular weights for PEG spacers used in accordance with the invention may, for example, be between 120 Daltons and 20 kDaltons.
The major mechanism for uptake of particles by the cells of the reticuloendothelial system (RES) is opsonisation by plasma proteins in blood; these mark foreign particles which are then taken up by the RES. The biological properties of PEG spacer elements used in accordance with the invention may serve to increase contrast agent circulation time in a similar manner to that observed for PEGylated liposomes (see e.g. Klibanov, A. L. et al. in FEBS Letters (1990) 268, 235-237 and Blume, G. and Cevc, G. in Biochim. Biophys. Acta (1990) 1029, 91-97).
Other potentially useful protein modifications which can be made to vectors include partial or complete deglycosidation by neuraminidase, endoglycosydases or periodate, since deglycosidation often results in less uptake by liver, spleen, macrophages etc., whereas neo-glycosylation of proteins often results in increased uptake by the liver and macrophages); preparation of truncated forms by proteolytic cleavage, leading to reduced size and shorter half life in circulation; and cationisation, e.g. as described by Kumagi et al. in J. Biol. Chem. (1987) 262, 15214-15219; Triguero et al. in Proc. Natl. Acad. Sci. USA (1989) 86, 4761-4765; Pardridge et al. in J. Pharmacol. Exp. Therap. (1989) 251, 821-826 and Pardridge and Boado, Febs Lett. (1991) 288, 30-32.
Increased coupling efficiency to areas of interest may also be achieved using antibodies bound to the terminii of PEG spacers (see e.g. Maruyama, K. et al. in Biochim. Biophys. Acta (1995) 1234, 74-80 and Hansen, C. B. et al. in Biochim. Biophys. Acta (1995) 1239, 133-144).
In some instances it is considered advantageous to include a PEG component as a stabiliser in conjunction with a vector or vectors or directly to the reporter in the same molecule where the PEG does not serve as a spacer.
Other representative spacer elements include structural-type polysaccharides such as polygalacturonic acid, glycosaminoglycans, heparinoids, cellulose and marine polysaccharides such as alginates, chitosans and carrageenans; storage-type polysaccharides such as starch, glycogen, dextran and aminodextrans; polyamino acids and methyl and ethyl esters thereof, as in homo- and co-polymers of lysine, glutamic acid and aspartic acid; and polypeptides, oligonucleotides and oligosaccharides, which may or may not contain enzyme cleavage sites.
In general, spacer elements may contain cleavable groups such as vicinal glycol, azo, sulfone, ester, thioester or disulphide groups. Spacers containing biodegradable methylene diester or diamide groups of formula
xe2x80x94(Z)m.Y.X.C(R1R2).X.Y.(Z)nxe2x80x94
[where X and Z are selected from xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94, and xe2x80x94NRxe2x80x94 (where R is hydrogen or an organic group); each Y is a carbonyl, thiocarbonyl, sulphonyl, phosphoryl or similar acid-forming group: m and n are each zero or 1; and R1 and R2 are each hydrogen, an organic group or a group xe2x80x94X.Y.(Z)mxe2x80x94, or together form a divalent organic group] may also be useful; as discussed in, for example, WO-A-9217436 such groups are readily biodegraded in the presence of esterases, e.g. in vivo, but are stable in the absence of such enzymes. They may therefore advantageously be linked to therapeutic agents to permit slow release thereof.
Poly[N-(2-hydroxyethyl)methacrylamides] are potentially useful spacer materials by virtue of their low degree of interaction with cells and tissues (see e.g. Volfovxc3xa1, I., Rxc3xadhovxc3xa1, B. and V. R. and Vetvicka, P. in J. Bioact. Comp. Polymers (1992) 7, 175-190). Work on a similar polymer consisting mainly of the closely related 2-hydroxypropyl derivative showed that it was endocytosed by the mononuclear phagocyte system only to a rather low extent (see Goddard, P., Williamson, I., Bron, J., Hutchkinson, L. E., Nicholls, J. and Petrak, K. in J. Bioct. Compat. Polym. (1991) 6, 4-24.).
Other potentially useful poymeric spacer materials include:
i) copolymers of methyl methacrylate with methacrylic acid; these may be erodible (see Lee, P. I. in Pharm. Res. (1993) 10, 980) and the carboxylate substituents may cause a higher degree of swelling than with neutral polymers;
ii) block copolymers of polymethacrylates with biodegradable polyesters (see e.g. San Roman, J. and Guillen-Garcia, P. in Biomaterials (1991) 12, 236-241);
iii) cyanoacrylates, i.e. polymers of esters of 2-cyanoacrylic acidxe2x80x94these are biodegradable and have been used in the form of nanoparticles for selective drug delivery (see Forestier, F., Gerrier, P., Chaumard, C., Quero, A. M., Couvreur, P. and Labarre, C. in J. Antimicrob. Chemoter. (1992) 30, 173-179);
iv) polyvinyl alcohols, which are water-soluble and generally regarded as biocompatible (see e.g. Langer, R. in J. Control. Release (1991) 16, 53-60);
v) copolymers of vinyl methyl ether with maleic anhydride, which have been stated to be bioerodible (see Finne, U., Hannus, M. and Urtti, A. in Int. J. Pharm. (1992) 78. 237-241);
vi) polyvinylpyrrolidones, e.g. with molecular weight less than about 25,000, which are rapidly filtered by the kidneys (see Hespe, W., Meier, A. M. and Blankwater, Y. M. in Arzeim.-Forsch./Drug Res. (1977) 27, 1158-1162);
vii) polymers and copolymers of short-chain aliphatic hydroxyacids such as glycolic, lactic, butyric, valeric and caproic acids (see e.g. Carli, F. in Chim. Ind. (Milan) (1993) 75, 494-9), including copolymers which incorporate aromatic hydroxyacids in order to increase their degradation rate (see Imasaki, K., Yoshida, M., Fukuzaki, H., Asano, M., Kumakura, M., Mashimo, T., Yamanaka, H. and Nagai. T. in Int. J. Pharm. (1992) 81, 31-38);
viii) polyesters consisting of alternating units of ethylene glycol and terephthalic acid, e.g. DacronR, which are non-degradable but highly biocompatible;
ix) block copolymers comprising biodegradable segments of aliphatic hydroxyacid polymers (see e.g. Younes, H., Nataf, P. R., Cohn, D., Appelbaum, Y. J., Pizov, G. and Uretzky, G. in Biomater. Artif. Cells Artif. Organs (1988) 16, 705-719), for instance in conjunction with polyurethanes (see Kobayashi, H., Hyon, S. H. and Ikada, Y. in xe2x80x9cWater-curable and biodegradable prepolymersxe2x80x9dxe2x80x94J. Biomed. Mater. Res. (1991) 25, 1481-1494);
x) polyurethanes, which are known to be well-tolerated in implants, and which may be combined with flexible xe2x80x9csoftxe2x80x9d segments, e.g. comprising poly(tetra methylene glycol), poly(propylene glycol) or poly(ethylene glycol)) and aromatic xe2x80x9chardxe2x80x9d segments, e.g. comprising 4,4xe2x80x2-methylenebis(phenylene isocyanate) (see e.g. Ratner, B. D., Johnston, A. B. and Lenk, T. J. in J. Biomed. Mater. Res: Applied Biomaterials (1987) 21, 59-90; Sa Da Costa, V. et al. in J. Coll. Interface Sci. (1981) 80, 445-452 and Affrossman, S. et al. in Clinical Materials (1991) 8, 25-31);
xi) poly(1,4-dioxan-2-ones), which may be regarded as biodegradable esters in view of their hydrolysable ester linkages (see e.g. Song, C. X., Cui, X. M. and Schindler, A. in Med. Biol. Eng. Comput. (1993) 31, S147-150), and which may include glycolide units to improve their absorbability (see Bezwada, R. S., Shalaby, S. W. and Newman, H. D. J. in Agricultural and synthetic polymers: Biodegradability and utilization (1990) (ed Glass, J. E. and Swift, G.), 167-174xe2x80x94ACS symposium Series, #433, Washington D.C., U.S.A.xe2x80x94American Chemical Society);
xii) polyanhydrides such as copolymers of sebacic acid (octanedioic acid) with bis(4-carboxy-phenoxy)propane, which have been shown in rabbit studies (see Brem, H., Kader, A., Epstein, J. I., Tamargo, R. J., Domb, A., Langer, R. and Leong, K. W. in Sel. Cancer Ther. (1989) 5, 55-65) and rat studies (see Tamargo, R. J., Epstein, J. I., Reinhard, C. S., Chasin, M. and Brem, H. in J. Biomed. Mater. Res. (1989) 23, 253-266) to be useful for controlled release of drugs in the brain without evident toxic effects;
xiii) biodegradable polymers containing ortho-ester groups, which have been employed for controlled release in vivo (see Maa, Y. F. and Heller, J. in J. Control. Release (1990) 14, 21-28); and
xiv) polyphosphazenes, which are inorganic polymers consisting of alternate phosphorus and nitrogen atoms (see Crommen, J. H., Vandorpe, J. and Schacht, E. H. in J. Control. Release (1993) 24, 167-180).
The following tables list linking agents and agents for protein modification which may be useful in preparing targetable contrast agents in accordance with the invention.
Linking agents used in accordance with the invention will in general bring about linking of vector to reporter or reporter to reporter with some degree of specificity, and may also be used to attach one or more therapeutically active agents.
Ultrasound imaging modalities which may be used in accordance with the invention include two- and three-dimensional imaging techniques such as B-mode imaging (for example using the time-varying amplitude of the signal envelope generated from the fundamental frequency of the emitted ultrasound pulse, from sub-harmonics or higher harmonics thereof or from sum or difference frequencies derived from the emitted pulse and such harmonics, images generated from the fundamental frequency or the second harmonic thereof being preferred), colour Doppler imaging and Doppler amplitude imaging, and combinations of the two latter with any of the modalities (techniques) above. Surprisingly, the second harmonic signals from the targeted monolayer microspheres were found to be excellent when used in accordance with the present invention. To reduce the effects of movement, successive images of tissues such as the heart or kidney may be collected with the aid of suitable synchronisation techniques (e.g. gating to the ECG or respiratory movement of the subject). Measurement of changes in resonance frequency or frequency absorption which accompany arrested or retarded microbubbles may also usefully be made to detect the contrast agent.
The present invention provides a tool for therapeutic drug delivery in combination with vector-mediated direction of the product to the desired site. By xe2x80x9ctherapeuticxe2x80x9d or xe2x80x9cdrugxe2x80x9d is meant an agent having a beneficial effect on a specific disease in a living human or non-human animal. Whilst combinations of drugs and ultrasound contrast agents have been proposed in, for example, WO-A-9428873 and WO-A-9507072, these products lack vectors having affinity for particular sites and thereby show comparitively poor specific retention at desired sites prior to or during drug release.
Therapeutic compounds used in accordance with the present invention may be encapsulated in the interior of the microbubbles or attached to or incorporated in the encapsulating walls. Thus, the therapeutic compound may be linked to a part of the wall, for example through covalent or ionic bonds, or may be physically mixed into the encapsulating material, particularly if the drug has similar polarity or solubility to the membrane material, so as to prevent it from leaking out of the product before it is intended to act in the body. The release of the drug may be initiated merely by wetting contact with blood following administration or as a consequence of other internal or external influences, e.g. dissolution processes catalyzed by enzymes or the use of of ultrasound. The destruction of gas-containing microparticles using external ultrasound is a well known phenomenon in respect of ultrasound contrast agents, e.g. as described in WO-A-9325241; the rate of release may be varied depending on the type of therapeutic application, using a specific amount of ultrasound energy from the transducer.
The therapeutic agent may be covalently linked to the encapsulating membrane surface using a suitable linking agent, e.g. as described herein. Thus, for example, one may initially prepare a phospholipid or lipopeptide derivative to which the drug is bonded through a biodegradable or selectively cleavable linker followed by incorporation of the material into the microbubble. Alternatively lipidated drug molecules which do not require processing to liberate an active drug are incorporated directly into the membrane. The active lipidated-drug can be released by increasing the strength of the ultrasound beam.
Exemplary drug delivery systems suitable for use in the present compositions include any known therapeutic drugs or active analogues thereof containing thiol groups which are coupled to thiol containing microbubbles under oxidative conditions yielding disulphide bridges. In combination with a vector or vectors the drug/vector modified microbubbles are allowed to accumulate in the target tissue. Administration of a reducing agent such as reduced glutathione then liberates the drug molecule from the targeted microbubble in the vicinity of the target cell increasing the local concentration of the drug and enhancing therapeutic effect. The product may also be prepared without the therapeutic if desired. The drug may then be coupled to or coated on the microbubbles prior to use. Thus, for example, a therapeutic could be added to a suspension of microbubbles in aqueous media and shaken in order to attach or adhere the therapeutic to the microbubbles.
Other drug delivery systems include vector modified phospholipid membranes doped with lipopeptide structures comprising a poly-L-lysine or poly-D-lysine chain in combination with a targeting vector. Applied to gene therapy/antisense technologies with particular emphasis on receptor-mediated drug delivery the microbubble carrier is condensed with DNA or RNA via elecrostatic interaction with the polycation. This method has the advantage that the vector or vectors used for targeted delivery are not directly attached to the polysine carrier moiety. The polylysine chain is also anchored more tightly in the microbubble membrane due to the presence of the lipid chains. The use of ultrasound to increase the effectiveness of delivery is also considered useful.
Alternatively free polylysine chains are firstly modified with drug or vector molecules then condensed onto the negative surface of targeted microbubbles.
Representative and non-limiting examples of drugs useful in accordance with the invention include antineoplastic agents such as vincristine, vinblastine, vindesine, busulfan, chlorambucil, spiroplatin, cisplatin, carboplatin, methotrexate, adriamycin, mitomycin, bleomycin, cytosine arabinoside, arabinosyl adenine, mercaptopurine, mitotane, procarbazine, dactinomycin (antinomycin D), daunorubicin, doxorubicin hydrochloride, taxol, plicamycin, aminoglutethimide, estramustine, flutamide, leuprolide, megestrol acetate, tamoxifen, testolactone, trilostane, amsacrine (m-AMSA), asparaginase (L-asparaginase), etoposide, interferon a-2a and 2b, blood products such as hematoporphyrins or derivatives of the foregoing; biological response modifiers such as muramylpeptides; antifungal agents such as ketoconazole, nystatin, griseofulvin, flucytosine, miconazole or amphotericin B; hormones or hormone analogues such as growth hormone, melanocyte stimulating hormone, estradiol, beclomethasone dipropionate, betamethasone, cortisone acetate, dexamethasone, flunisolide, hydrocortisone, methylprednisolone, paramethasone acetate, prednisolone, prednisone, triamcinolone or fludrocortisone acetate; vitamins such as cyanocobalamin or retinoids; enzymes such as alkaline phosphatase or manganese superoxide dismutase; antiallergic agents such as amelexanox; inhibitors of tissue factor such as monoclonal antibodies and Fab fragments thereof, synthetic peptides, nonpeptides and compounds downregulating tissue factor expression; inhibitors of platelets such as, GPIa, GPIb and GPIIb-IIIa, ADP receptors, thrombin receptors, von Willebrand factor, prostaglandins, aspirin, ticlopidin, clopigogrel and reopro; inhibitors of coagulation protein targets such as: FIIa FVa, FVIIa, FVIIIA, FIXa, tissue factor, hepatins, hirudin, hirulog, argatroban, DEGR-rFVIIa and annexin V; inhibitors of fibrin formation and promoters of fibrionolysis such as t-PA, urokinase, Plamin, Streptokinase, rt-Plasminogen Activator and rstaphylokinase; antiangiogenic factors such as medroxyprogesteron, pentosan polysulphate, suramin, taxol, thalidomide, angiostatin, interferon-alpha, metalloproteinase inhibitors, platelet factor 4, somatostatin, thromobospondin; circulatory drugs such as propranolol; metabolic potentiators such as glutathione; antituberculars such as p-aminosalicylic acid, isoniazid, capreomycin sulfate, cyclosexine, ethambutol, ethionamide, pyrazinamide, rifampin or streptomycin sulphate; antivirals such as acyclovir, amantadine, azidothymidine, ribavirin or vidarabine; blood vessel dilating agents such as diltiazem, nifedipine, verapamil, erythritol tetranitrate, isosorbide dinitrate, nitroglycerin or pentaerythritol tetranitrate; antibiotics such as dapsone, chloramphenicol, neomycin, cefaclor, cefadroxil, cephalexin, cephradine, erythromycin, clindamycin, lincomycin, amoxicillin, ampicillin, bacampicillin, carbenicillin, dicloxacillin, cyclacillin, picloxacillin, hetacillin, methicillin, nafcillin, penicillin, polymyxin or tetracycline; antiinflammatories such as diflunisal, ibuprofen, indomethacin, meclefenamate, mefenamic acid, naproxen, phenylbutazone, piroxicam, tolmetin, aspirin or salicylates; antiprotozoans such as chloroquine, metronidazole, quinine or meglumine antimonate; antirheumatics such as penicillamine; narcotics such as paregoric; opiates such as codeine, morphine or opium; cardiac glycosides such as deslaneside, digitoxin, digoxin, digitalin or digitalis; neuromuscular blockers such as atracurium mesylate, gallamine triethiodide, hexafluorenium bromide, metocurine iodide, pancuronium bromide, succinylcholine chloride, tubocurarine chloride or vecuronium bromide; sedatives such as amobarbital, amobarbital sodium, apropbarbital, butabarbital sodium, chloral hydrate, ethchlorvynol, ethinamate, flurazepam hydrochloride, glutethimide, methotrimeprazine hydrochloride, methyprylon, midazolam hydrochloride, paraldehyde, pentobarbital, secobarbital sodium, talbutal, temazepam or triazolam; local anaesthetics such as bupivacaine, chloroprocaine, etidocaine, lidocaine, mepivacaine, procaine or tetracaine; general anaesthetics such as droperidol, etomidate, fentanyl citrate with droperidol, ketamine hydrochloride, methohexital sodium or thiopental and pharmaceutically acceptable salts (e.g. acid addition salts such as the hydrochloride or hydrobromide or base salts such as sodium, calcium or magnesium salts) or derivatives (e.g. acetates) thereof. Other examples of therapeutics include genetic material such as nucleic acids, RNA, and DNA of natural or synthetic origin, including recombinant RNA and DNA. DNA encoding certain proteins may be used in the treatment of many different types of diseases. For example, tumor necrosis factor or interleukin-2 genes may be provided to treat advanced cancers; thymidine kinase genes may be provided to treat ovarian cancer or brain tumors; interleukin-2 genes may be provided to treat neuroblastoma, malignant melanoma or kidney cancer; and interleukin-4 genes may be provided to treat cancer.
Lipophilic derivatives of drugs linked to the microbubble wall through hydrophobic interactions may exhibit therapeutic effects as part of the microbubble or after release from the microbubble, e.g. by use of ultrasound. If the drug does not possess the desired physical properties, a lipophilic group may be introduced for anchoring the drug to the membrane. Preferably the lipophilic group should be introduced in a way that does not influence the in vivo potency of the molecule, or the lipophilic group may be cleaved releasing the active drug. Lipophilic groups may be introduced by various chemical means depending on functional groups available in the drug molecule. Covalent coupling may be effected using functional groups in the drug molecule capable of reacting with appropriately functionalised lipophilic compounds. Examples of lipophilic moieties include branched and unbranched alkyl chains, cyclic compounds, aromatic residues and fused aromatic and non-aromatic cyclic systems. In some instances the lipophilic moiety will consist of a suitably functionalised steroid, like cholesterol and related compounds. Examples of functional groups particularly suitable for derivatisation include nucleophilic groups like amino, hydroxy and sulfhydryl groups. Suitable processes for lipophilic derivatisation of any drug containing a sulfhydryl group, like captopril, may include direct alkylation, e.g. reaction with an alkyl halide under basic conditions and thiol ester formation by reaction with an activated carboxylic acid. Representative examples of derivatisation of any drug having carboxylic functions, like atenolol and chlorambucil, include amide and ester formation by coupling of amines and alcohols, respectively, possesing requested physical properties. A preferred aspect is attachment of cholesterol to a therapeutic compound by forming a degradable ester bond.
A preferred application of the present invention relates to angiogenesis, which is the formation of new blood vessels by branching from existing vessels. The primary stimulus for this process may be inadequate supply of nutrients and oxygen (hypoxia) to cells in a tissue. The cells may respond by secreting angiogenetic factors, of which there are many; one example is vascular endothelial growth factor. These factors initiate the secretion of proteolytic enzymes which break down the proteins of the basement membrane, as well as inhibitors which limit the action of these potentially harmful enzymes. The combined effect of loss of attachment and signals from the receptors for angiogenetic factors is to cause the endothelial cells to move, multiply, and rearrange themselves, and finally to synthetise a basement membrane around the new vessels.
Tumors must initiate angiogenesis when they reach millimeter size in order to keep up their rate of growth. As angiogenesis is accompanied by characteristic changes in the endothelial cells and their environment, this process is a promising target for therapeutic intervention. The transformations accompanying angiogenesis are also very promising for diagnosis, a preferred example being malignant disease, but the concept also shows great promise in inflammation and a variety of inflammation-related diseases. These factors are also involved in re-vascularisation of infarcted parts of the myocardium, which occurs if a stenosis is released within a short time.
A number of known receptors/targets associated with angiogenesis are given in subsequent tables. Using the targeting principles described in the present disclosure, angiogenesis may be detected by the majority of the imaging modalities in use in medicine. Contrast-enhanced ultrasound may possess additional advantages, the contrast medium being microspheres which are restricted to the interior of blood vessels. Even if the target antigens are found on many cell types, the microspheres will attach exclusively to endothelial cells.
So-called prodrugs may also be used in agents according to the invention. Thus drugs may be derivatised to alter their physicochemical properties and to adapt them for inclusion into the reporter; such derivatised drugs may be regarded as prodrugs and are usually inactive until cleavage of the derivatising group regenerates the active form of the drug.
By targeting a gas-filled microbubble containing a prodrug-activating enzyme to areas of pathology one may image targeting of the enzyme, making it possible to visualise when the microbubbles are targeted properly to the area of pathology and at the same time have disappeared from non-target areas. In this way one can determine the optimal time for injection of prodrug into individual patients.
Another alternative is to incorporate the prodrug, the prodrug-activating enzyme and the vector in the same microbubble in a system where the prodrug will only be activated after some external stimulus. Such a stimulus may, for example, be a tumour-specific protease as described above, or bursting of the bubbles by external ultrasound after the desired targeting has been achieved.
Therapeutics may easily be delivered in accordance with the invention to diseased or necrotic areas including the heart and vasculature in general, and to the liver, spleen and kidneys and other regions such as the lymph system, body cavities or gastrointestinal system.
Products according to the present invention may be used for targeted therapeutic delivery either in vivo or in vitro. In the latter context the products may be useful in in vitro systems such as kits for diagnosis of different diseases or characterisation of different components in blood or tissue samples. Similar techniques to those used to attach certain blood components or cells to polymer particles(e.g. monodisperse magnetic particles) in vitro to separate them from a sample may be used in the present invention, using the low density of the reporter units in agents of the present invention to effect separation of the gas-containing material by floatation and repeated washing.
Vectors which may be usefully employed in generating multiple-specific targetable contrast agents according to the invention include the following:
i) Antibodies, which can be used as vectors for a very wide range of targets, and which have advantageous properties such as very high specificity, high affinity (if desired), the possiblity of modifying affinity according to need etc. Whether or not antibodies will be bioactive will depend on the specific vector/target combination. Both conventional and genetically engineered antibodies may be employed, the latter permitting engineering of antibodies to particular needs, e.g. as regards affinity and specificity. The use of human antibodies may be preferred to avoid possible immune reactions against the vector molecule. A further useful class of antibodies comprises so-called bispecific antibodies, i.e. antibodies having specificity for two different target molecules in one antibody molecule. Such antibodies may, for example, be useful in promoting formation of bubble clusters and may also be used for various therapeutic purposes, e.g. for carrying toxic moieties to the target. Various aspects of bispecific antibodies are described by McGuinness, B. T. et al. in Nat. Biotechnol. (1996) 14, 1149-1154; by George, A. J. et al. in J. Immunol. (1994) 152, 1802-1811; by Bonardi et al. in Cancer Res. (1993) 53, 3015-3021; and by French, R. R. et al. in Cancer Res. (1991) 51, 2353-2361.
ii) Cell adhesion molecules, their receptors, cytokines, growth factors, peptide hormones and pieces thereof. Such vectors rely on normal biological proteinxe2x80x94protein interactions with target molecule receptors, and so in many cases will generate a biological response on binding with the targets and thus be bioactive; this may be a relatively insignificant concern with vectors which target proteoglycans.
iii) Non-peptide agonists/antagonists or non-bioactive binders of receptors for cell adhesion molecules, cytokines, growth factors and peptide hormones. This category may include non-bioactive vectors which will be neither agonists nor antagonist but which may nonetheless exhibit valuable targeting ability.
iv) Oligonucleotides and modified oligonucleotides which bind DNA or RNA through Watson-Crick or other types of base-pairing. DNA is usually only present in extracellular space as a consequence of cell damage, so that such oligonucleotides, which will usually be non-bioactive, may be useful in, for example, targeting of necrotic regions, which are associated with many different pathological conditions. Oligonucleotides may also be designed to bind to specific DNA- or RNA-binding proteins, for example transcription factors which are very often highly overexpressed or activated in tumour cells or in activated immune or endothelial cells. Combinatorial libraries may be used to select oligonucleotides which bind specifically to possible target molecules (from proteins to caffeine) and which therefore may be employed as vectors for targeting.
v) DNA-binding drugs may behave similarly to oligonuclotides, but may exhibit biological activity and/or toxic effects if taken up by cells.
vi) Various small molecules, including bioactive compounds known to bind to biological receptors of various kinds. Such vectors or their targets may be used to generate non-bioactive compounds binding to the same targets.
vii) Vector molecules may be selected from combinatorial libraries without necessarily knowing the exact molecular target, by functionally selecting (in vitro, ex vivo or in vivo) for molecules binding to the region/structure to be imaged.
viii) Various small molecules, including bioactive compounds known to bind to biological receptors of various kinds. Such vectors or their targets may be used for generate non-bioactive compounds binding to the same targets.
ix) Proteins or peptides which bind to glucosamino-glycan side chains e.g. haparan sulphate, including glucosoaminoglycan-binding portions of larger molecules, since binding to such glucosoaminoglycans side chains does not result in a biological response. Proteoglycans are not found on red blood cells, thus eliminating undesirable adsorption to these cells.
Other peptide vectors and lipopeptides thereof of particular interest for targeted ultrasound imaging are listed below: Atherosclerotic plaque binding peptides such as YRALVDTLK, YAKFRETLEDTRDRMY and RALVDTEFKVKQEAGAK; Thrombus binding peptides such as NDGDFEEIPEEYLQ and GPRG; Platelet binding peptides such as PLYKKIIKKLLES; and cholecystokinin, xcex1-melanocyte-stimulating hormone, heat stable enterotoxin 1, vasoactive intestinal peptide, synthetic alpha-M2 peptide from the third heavy chain complementarity-determining region and analogues thereof for tumor targeting.
The following tables identify various receptors which may be targeted by particular types of vectors and consequent areas of use for targetable ultrasound contrast agents according to the invention which contain such vectors.
Representative examples of drugs useful in accordance with the invention include: abamectin, abundiazole, acaprazine, acabrose, acebrochol, aceburic acid, acebutolol, acecainide, acecarbromal, aceclidine, aceclofenac, acedapsone, acediasulfone, acedoben, acefluranol, acefurtiamine, acefylline clofibrol, acefylline piperazine, aceglatone, aceglutamide, aceglutamide aluminium, acemetacin, acenocoumarol, aceperone, acepromazine, aceprometazine, acequinoline, acesulfame, acetaminophen, acetaminosalol, acetanilide, acetarsone, acetazolamide, acetergamine, acetiamine, acetiromate, acetohexamide, acetohydroxamic acid, acetomeroctol, acetophenazine, acetorphine, acetosulfone, acet: ozate, acetryptine, acetylcholine chloride, acetylcolchinol, acetylcysteine, acetyldigitoxin, acetylleucine, acetylsalicyclic acid, acevaltrate, acexamic acid, acifran, acipimox, acitemate, acitretin, acivicin, aclantate, aclarubicin, aclatonium napadisilate, acodazole, aconiazide, aconitine, acoxatrine, acridorex, acrihellin, acrisorcin, acrivastine, acrocinide, acronine, actinoquinol, actodigin, acyclovir, adafenoxate, adamexine, ademetionine, adenosine phosphate, adibendan, adicillin, adimolol, adinazolam, adiphenine, aditeren, aditoprim, adrafinil, adrenalone, afloqualone, afurolol, aganodine, ajmaline, aklomide, alacepril, alafosfalin, alanine mustard, alanosine, alaproclate, alazanine triclofenate, albendazole, albendazole oxide, albuterol, albutoin, alclofenac, alcometasone dipropionate, alcloxa, alcuronium chloride, aldioxa, aldosterone, alepride, aletamine, alexidine, alfacalcidol, alfadex, alfadolone, alfaprostol, alfaxalone, alfentanil, alfuzosin, algestone acetonide, algestone acetophenide, alibendol, aliconazole, alifedrine, aliflurane, alimadol, alinidine, alipamide, alitame, alizapride, allantoin, alletorphine, allobarbital, alloclamide, allocupreide, allomethadione, allopurinol, allylestrenol, allyl isothicyanate, allylprodine, allylthiourea, almadrate sulfate, almasilate, almecillin, almestrone, alminoprofen, almitrine, almoxatone, alonacic, alonimid, aloxistatin, alozafone, alpertine, alphacetylmethadol, alphameprodine, alphamethadol, alphaprodine, alpha-vinylaziridinoethyl acetate, alpidem, alpiropride, alprazolam, alprenolol, alprostadil, alrestatin, altanserin, altapizone, alteconazole, althiazide, altrenogest, altretamine, aluminium acetate, aluminium clofibrate, aluminium subacetate, alverine, amadinone acetate, amafolone, amanozine, amantadine, amantanium bromide, amantocillin, ambasilide, ambazone, ambenonium chloride, ambenoxan, ambroxol, ambruticin, ambucaine, ambucetamide, ambuphylline, ambuside, ambutonium bromide, amcinafal, amcinafide, amcinonide, amdinocillin, amdinocillin pivoxil, amebucort, amedalin, ametantrone, amezepine, amezinium metilsulfate, amfenac, amfepentorex, amfetaminil, amflutizole, amfonelic acid, amicarbalide, amicibone, amicloral, amicycline, amidantel, amidapsone, amidephrine, amiflamine, amifloverine, amifloxacin, amifostine, amikacin, amikhelline, amiloride, aminacrine, amindocate, amineptine, aminobenzoic acid, aminocaproic acid, aminoethyl nitrate, aminoglutethimide, aminohippuric acid, aminometradine, aminopentamide, aminophylline, aminopromazine, aminopterin, aminopyrine, aminoquinol, aminoquinuride, aminorex, aminosalicyclic acid, aminothiadiazole, aminothiazole, amiodarone, amiperone, amipheazole, amipizone, amiprilose, amiquinsin, amisometradine, amisulpride, amiterol, amithiozone, amitraz, amitriptyline, amitriptylinoxide, amixetrine, amlexanox, amlodipine, amobarbital, amodiaquine, amogastrin, amolanone, amonofide, amoproxan, amopyroquin, amorolfine, amocanate, amosulalol, amotriphene, amoxapine, amoxecaine, amoxicillin, amoxydramine camsilate, amperozide, amphecloral, amphenidone, amphetamine, amphotalide, amphotericin B, ampicillin, ampiroxicam, amprolium, ampyrimine, ampyzine, amquinate, amrinone, amsacrine, amygdalin, amylene, amylmetacresol, amyl nitrite, anagestone acetate, anagrelide, anaxirone, anazocine, anazolene, ancarolol, ancitabine, androstanediol, androstanol propionate, androstenetrione, androstenonol propionate, anethole, anguidine, anidoxime, anilamate, anileridine, aniline, anilopam, anipamil, aniracetam, anirolac, anisacril, anisindione, anisopirol, anisoylbromacrylic acid, anitrazafen, anpirtoline, ansoxetine, antafenite, antazoline, antazonite, anthelmycin, anthiolimine, anthralin, anthramycin, antienite, antimony potassium tartrate, antimony thioglycollate, antipyrine, antrafenine, apalcillin, apazone, apicycline, apomorphine, apovincamine, apraclonidine, apramycin, aprindine, aprobarbital, aprofene, aptazapine, aptocaine, arabinosylmercaptopurine, aranotin, arbaprostil, arbekacin, arclofenin, arfendazam, arginine, arginine glutamat, arildone, arnolol, aronixil, arotinolol, arpinocid, arpromidine, arsanilic acid, arsthinol, artemisinin, articaine, asaley, ascorbic acid, ascorbyl palmitate, asocainol, aspartame, aspartic acid, asperlin, aspoxicillin, astemizole, atamestane, atenolol, atipamezole, atiprosin, atolide, atracurium besilate, atromepine, atropine, atropine oxide, auranofin, aurothoiglucose, aurothioglycanide, avilamycin-A, avridine, axamozide, azabon, azabuperone, azacitodine, azaclorzine, azaconazole, azacosterol, azacyclonol, azaftozine, azaguanidine, azaloxan, azamethonium bromide, azamulin, azanator, azanidazole, azaperone; azapicyl, azaprocin, azaquinzole, azaribine, azarole, azaserine, azaspirium chloride, azastene, azastrptonigrin, azatodine, azathioprine, azauridine, azelastine, azepexole, azepindole, azetepa, azidamfenicol, azidocillin, azimexon, azintamide, azipramine, azithromycin, azlocillin, azolimine, azosemide, azotomycin, aztreonam, azumolene, bacampicillin, baclofen, bacmecillinam, balsalazide, bamaluzole, bambuterol, bamethan, bamifylline, bamipine, bamnidazole, baquiloprim, barbexaclone, barbital, barucainide, batilol, bazinaprine, becanthone, beclamide, beclobrate, beclomethasone dipropionate, beclotiamine, befiperide, befunolol, befuraline, bekanamycin, belarizine, beloxamide, bemarinone, bemegride, bemetizide, bemitradine, benactyzine, benafentrine, benanserin, benapryzine, benaxibine, benazepril, bencianol, bencisteine, benclonidine, bencyclane, bendamustine, bendazac, bendazol, benderizine, bendroflumethiazide, benethamide penicillin, benexate, benflorex, benfosformin, benfotiamine, benfurodil hemisuccinate, benhepazone, benidipine, benmoxin, benolizime, benorilate, benorterone, benoxafos, benoxaprofen, benoxinate, benperidol, benproperine, benrixate, bensalan, benserazide, bensuldazic acid, bentazepam, bentemazole, bentiamine, bentipimine, bentiromide, benurestat, benzaldehyde, benzalkonium chloride, benzaprinoxide, benzarone, benzbromarone, benzestrol, benzethidine, benzethonium chloride, benzetimide, benzilonium bromide, benzindopyrine, benziodarone, benzmalecene, benznidazole, benzobarbital, benzocaine, benzoclidine, benzoctamide, benzodepa, benzododecinium chloride, benzoic acid, benzoin, benzonatate, benzopyrronium bromide, benzoquinium chloride, benzotript, benzoxiquine, benzoxonium chloride, benzoyl peroxide, benzoylpas, benzphetamine, benzpiperylon, benzpyrinium bromide, benzquercin, benzquinamide, benzthiazide, benztropine, benzydamine, benzylpenicillin, benzylsulfamide, beperidium iodide, bephenium naphtoate, bepiastine, bepridil, beraprost, berberine sulfate, bermastine, bermoprofen, berythromycin, besulpamide, beslunide, beta carotene, betacetylmethadol, betahistine, betaine, betameprodine, betamethadol, betamethasone, betamethasone acetate, betamethasone acibutate, betamethasone benzoate, betamethasone dipropionate, betamethasone phosphate, betamethasone valerate, betamicin, betaprodine, betaxolol, betazole, bethanechol chloride, bethanidine, betiatide, betoxycaine, bevantolol, bevonium metilsulfate, bezafibrate, bezitramide, bialamicol, bibenzonium bromide, bibrocathol, bicifadine, biclodil, biclofibrate, biclotymol, bicozamycin, bidimazium iodine, bietamiverine, bietaserpine, bifemelane, bifepramide, bifluranol, bifonazole, binedaline, binfloxacin, binfibrate, bioallethrin, bioresmethrin, biotin, bipenamol, biperiden, biphenamine, biriperone, bisacodyl, bisantrene, bis(aziridinyl) butanediol, bisbendazole, bisbentiamine, bisfenazone, bisfentidine, bismuth betanaphthol, bismuth-triglycollamate, bismuth subgallate, bismuth subsalicylate, bisorbin, bisoprolol, bisorcic, bioxatin acetate, bispyrithione magsulfex, bithionol, bithionoloxide, bitipazone, bitoterol, bitoscantate, bleomycin, bluensomycin, bofumustine, bolandiol dipropionate, bolasterone, bolazine, boldenone undecylenate, bolenol, bolmantalate, bometolol, bopindolol, bornaprine, bornaprolol, bornelone, botiacrine, boxidine, brallobarbital, brazergoline, brefonalol, bremazocine, brequinar, bretylium tosylate, brindoxime, brivundine, brobactam, broclepride, brocresine, brocrinat, brodimoprim, brofaromine, brofezil, brofoxine, brolaconazole, brolamfetamine, bromacrylide, bromadoline, bromamid, bromazepam, bromchlorenone, bromebric acid, bromerguride, brometenamine, bromfenac, bromhexine, bromindione, bromisovalum, bromociclen, bromocriptine, bromodiphenhydramine, bromofenofos, bromopride, bromoxandide, bromperidol, bromperidol decanoate, brompheniramine, bronopol, broparestrol, broperamole, bropirimine, broquinaldol, brosotamide, brosuximide, brotianide, brotizolam, brovanexine, brovincamine, broxaldine, broxaterol, broxitalamic acid, broxuridine, broxyquinoline, bruceantin, brucine, bucainide, bucetin, buciclovir, bucillamine, bucindolol, bucladesine, buclizine, buclosamide, bucloxic acid, bucolome, bucricaine, bucromarone, bucrylate, bucumolol, budesonide, budipine, budotitane, budralazine, bufenadrine, bufeniode, bufetolol, bufexamac, bufezolac, buflomedil, bufogenin, buformin, bufrolin, bufuralol, bumadizone, bumecaine, bumepidil, bumetanide, bumetrizole, bunaftine, bunamidine, bunamiodyl, bunaprolast, bunazosin, bunitrolol, bunolol, buparvaquone, bupicomide, bupivacaine, bupranolol, buprenorphine, bupropion, buquineran, buquinolate, buquiterine, buramate, burodiline, buspirone, busulfan, butabarbital, butacaine, butacetin, butaclamol, butadiazamide, butafosfan, butalamine, butalbital, butamben, butamirate, butamisole, butamoxane, butanediol cyclic sulfite, butanilicaine, butanixin, butanserin, butantrone, butaperazine, butaprost, butaverine, butedronate, buterizine, butetamate, butethamine, buthiazide, butibufen, butidrine, butikacin, butilfenin, butinazocine, butinoline, butirosin, butixirate, butobendine, butoconazole, butoprolol, butoctamide, butofilolol, butonate, butopamine, butopiprine, butoprozine, butopyrammonium iodide, butorphanol, butoxamine, butoxylate, butriptyline, butropium bromide, butylated hydroxyanisole, butylated hydroxytoluene, butylparaben, butynamine, buzepide metiodide, cabastine, cabergoline, cadralazine, cafaminol, cafedrine, caffeine, calcifediol, calcitrol, calcium citrate, calcium dobesilate, calcium glubionate, calcium gluceptate, calcium gluconate, calcium glycerophosphate, calcium hypophosphite, calcium lactate, calcium lactobionate, calcium levulinate, calcium mandelate, calcium pantothenate, calcium phosphate dibasic, calcium phophate tribasic, calcium saccharate, calcium stearate, calusterone, camazepam, cambendazole, camiverine, camostast, camphotamide, camptothecin, camylofin, canbisol, cannabinol, canrenoic acid, canrenone, cantharidine, capobenic acid, capreomycin, caproxamine, capsaicine, captamine, captodiame, captopril, capuride, caracemide, caramiphen, carazolol, carbachol, carbadox, carbaldrate, carbamazepine, carbamide peroxide, carbantel lauryl sulfate, carbaril, carbarsone, carbaspirin calcium, carbazeran, carbazochrome, carbazachrome salicylate, carbazachrome sulfonate, carbazocine, carbeniciltin, carbenicillin indanyl, carbencillin phenyl, carbenoxolone, carbenzide, carbestrol, carbetapentane, carbidopa, carbimazole, carbinoxamine, carbiphene, carbocloral, carbocysteine, carbofenotion, carbol-fuschin, carbomycin, carboplatin, carboprost, carboprost methyl, carboquone, carbromal, carbubarb, carburazepam, carbutamide, carbuterol, carcainium chloride, carebastine, carfentanil, carfimate, carisoprodol, carmantadine, carmetizide, carmofur, carmustine, carnidazole, carnitine, carocainide, caroverine, caroxazone, carperidine, caperone, carphenazine, carpindolol, carpiramine, carprofen, carpronium chloride, carsalam, cartazolate, carteolol, carubicin, carumonam, carvedilol, carzenide, carzolamide, cathine, cathinone, cefaclor, cefadroxil, cefaloniurm, cefaloram, cefamandole, cefamandole naftate, cefaparole, cefatrizine, cefazaflur, cefazedone, cefazolin, cefbuperazone, cefcanel, cefcanel daloxate, cefedrolor, cefempidone, cefepime, cefetamet, cefetrizole, cefvitril, cefixime, cefmenoxime, cefmepidium chloride, cefmetazole, cefminox, cefodizime, cefonizid, cefoperazone, ceforanide, cefotaxime, cefotetan, cefotiam, cefoxazole, cefoxitin, cefpimizole, cefpiramide, cefpirome, cefpodoxime, cefpodoxime proxetil, cefquinome, cefrotil, cefroxadine, cefsulodin, cefsumide, ceftazidime, cefteram, ceftezole, ceftiofur, ceftiolene, ceftioxide, ceftizoxime, ceftriaxone, cefuracetime, cefuroxime, cefuraxime axetil, cefurzonam, celiprolol, cephacetrile, cephalexin, cephaloglycin, cephaloridine, cephalothin, cephapirin, cephradine, cetaben, cetamolol, cethexonium chloride, cetiedil, cetirizine, cetocycline, cetohexazine, cetophenicol, cetotiamine, cetoxime, cetraxate, chaulmosulfone, chendiol, chiniofon, chlophedianol, chloracyzine, chloral betaine, chloral hydrate, chloralose, chlorambucil, chloramine, chloramphenicol, chloramphenicol palmitate, chloramphenicol succinate, chlorazanil, chlorbenzoxamine, chlorbetamide, chlorcyclizine, chlordantoin, chlordiazepoxide, chlordimorine, chlorhexadol, chlorhexidine, chlorhexidine phosphanilate, chlorindanol, chlorisondamine chloride, chlormadinone acetate, chlormerodrin, chlormezanone, chlormidazole, chloronaphazine, chloroazodin, chlorobutanol, chlorocresol, chlorodihydroxyandrostenone, chloroethyl mesylate, 5-chloro-3xe2x80x2-fluoro-2xe2x80x23-dideoxyuridine, chloroguanide, chlorophenothane, chloroprednisone acetate, chloroprocaine, chloropyramine, chloroquine, chloroserpidine, chlorothen, chlorothiazide, chlorotriansene, chloroxine, chloroxylenol, chlorozotocin, chlorphenesin, chlorphenesin carbamate, chlorpheniramine, chlorphenoctium amsonate, chlorphenoxamine, chlorphentermine, chlorproethazine, chlorproguanil, chlorpromazine, chlorpropamide, chlorprothixene, chlorquinaldol, chlortetracycline, chlorthalidone, chlorthenoxazine, chlorzoaxazone, chloecalciferol, cholic acid, choline chloride, choline glycerophosphate, chromocarb, chromonar, ciadox, ciamexon, cianergoline, cianidol, cianopramine, ciapilome, cicaprost, cicarperone, ciclactate, ciclafrine, ciclazindol, cicletanine, ciclomenol, ciclonicate, ciclonium bromide, ciclopirox, ciclopramine, cicloprofen, cicloprolol, ciclosidomine, ciclotizolam, ciclotropium bromide, cicloxilic acid, cicloxolone, cicortonide, cicrotic acid, cidoxepin, cifenline, cifostodine, ciglitazone, ciheptolane, ciladopa, cilastatine, cilazapril, cilazaprilat, cilobamine, cilofungin, cilostamide, cilostazol, ciltoprazine, cimaterol, cimemoxin, cimepanol, cimetidine, cimetropium bromide, cimoxatone, cinchonine, cinchophen, cinecromen, cinepaxadil, cinepazet, cinepazic acid, cinepazide, cinfenine, cinfenoac, cinflumide, cingestol, cinitapride, cinmetacin, cinnamaverine, cinnamedrine, cinnarizine, cinnarizine clofibrate, cinnofuradione, cincotramide, cinodine, cinolazepam, cinoquidox, cinoaxin, cinoxate, cinoxolone, cinooxopazide, cinperene, cinprazole, cinpropazide, cinromide, cintazone, cintriamide, cinperone, ciprafamide, ciprafazone, ciprefadol, ciprocinonide, ciprofibrate, ciprofloxacin, cipropride, ciproquazone, ciprostene, ciramadol, cirazoline, cisapride, cisconazole, cismadinone, cisplatin, cistinexine, citalopram, citatepine, citenamide, citenazone, citicoline, citiolone, clamidoxic acid, clamoxyquin, clanfenur, clanobutin, clantifen, clarithromycin, clavulanic acid, clazolam, clazolimine, clazuril, clebopride, clefamide, clemastine, clemeprol, clemizole, clenbuterol, clenpirin, cletoquine, clibucaine, clidafidine, clidanac, clidinum bromide, climazolam, climbazole, climiqualine, clindamycin, clindamycin palmitate, clindamycin phosphate, clinofibrate, clinolamide, cliquinol, clioxanide, clipoxamine, cliprofen, clobazam, clobenoside, clobenzepam, clobenzorex, clobenztropine, clobetasol propionate, clobetasone butyrate, clobutinol, clobuzarit, clocanfamide, clocapramine, clociguanil, clocinizine, clocortolone acetate, clocortolone pivalate, clocoumarol, clodacaine, clodanolene, clodazon, clodoxopone, clodronic acid, clofazimine, clofenamic acid, clofenamide, clofenciclan, clofenetamine, clofenoxyde, clofenvinfos, clofeverine, clofexamide, clofezone, clofibrate, clofibric acid, clofibride, clofilium phosphate, cloflucarban, clofoctol, cloforex, clofurac, clogestone acetate, cloguanamil, clomacran, clomegestone acetate, clometacin, clometherone, clomethiazole, clometocillin, clomifenoxide, clominorex, clomiphene, clomipramine, clomocycline, clomoxir, clonazepam, clonazoline, clonidine, clonitazene, clonitrate, clonixeril, clonixin, clopamide, clopenthixol, cloperastine, cloperidone, clopidogrel, clopidol, clopimozide, clopipazan, clopirac, cloponone, cloprednol, cloprostenol, cloprothiazole, cloquinate, cloquinozine, cloracetadol, cloranolol, clorazepate, clorethate, clorexolone, clorgiline, cloricromen, cloridarol, clorindanic acid, clorindione, clormecaine, cloroperone, clorophene, cloroqualone, clorotepine, clorprenaline, clorsulon, clortermine, closantel, closiramine, clostebol, clothiapine, clothixamide, clotiazepam, cloticasone propionate, clotioxone, clotrimazole, clovoxamine, cloxacepride, cloxacillin, cloxacillin benzathine, cloxazolam, cloxestradiol, cloximate, cloxotestosterone, cloxypendyl, cloxyquin, clozapine, cobamide, cocaine, cocarboxylase, codeine, codoxime, cofisatin, cogazocine., colchicine, colestolone, colfenamate, colforsin, colterol, conessine, conorphone, copper gluconate, cormethasone acetate, corticosterone, cortisone acetate, cortisuzol, cortivazol, cortodoxone, cotarnine chloride, cotinine, cotriptyline, coumaphos, coumazoline, coumermycin, coumetarol, creatinolfosfate, crisnatol, croconazole, cromakalim, cromitrile, cromolyn, cropropamide, crospovidone, crotamiton, crotetamide, crotoniazide, crufomate, cuprimyxin, cuproxoline, cyacetacide, cyamemazine, cyanocobalamine, cyclacillin, cyclandelate, cyclarbamate, cyclazocine, cyclazodone, cyclexanone, cyclindole, cycliramine, cyclizine, cyclobarbital, cyclobendazole, cyclobenzaprine, cyclobutoic acid, cyclobutyrol, cyclofenil, cycloguanil, cloheximide, cycloleucine, cyclomenol, cyclomethicone, cyclomethycaine, cyclopentamine, cyclopenthiazide, cyclopentolate, cyclopenazine, cyclophosphamide, cyclopregnol, cyclopyrronium bromide, cycloserine, cyclosporine, cyclothiazide, cyclovalone, cycotiamine, cycrimine, cyheptamide, cyheptropine, cynarine, cypenamine, cypothrin, cyprazepam, cyprenophine, cyprodenate, cyproheptadine, cyprolidol, cyproquinate, cyproterone acetate, cyproximide, cystine, cytarabine, dacarbazine, dacemazine, dacisteine, dacinomycin, dacuronium bromide, dagapamil, dalbraminol, daledalin, daltroban, dametralast, damotepine, danazol, danitracen, danosteine, danthron, dantrolene, dapiprazole, dapsone, daptomycin, darenzepine, darodipine, datelliptium chloride, dunorubicin, dazadrol, dazepinil, dazidamine, dazmegrel, dazolicine, dazopride, dazoquinast, dacoxiben, deanol aceglumate, deanol acetaminobenzoate, deazauridine, deboxamet, debrisoquin, decamethonium bromide, decimemide, decitropine, declaben, declenperone, decloxizine, decominol, decoquinate, deditonium bromide, deferoxamine, deflazacort, defosfamide, dehydroacetic acid, dehydroemetine, dehydro-7-methyltestosterone, delanterone, delapril, delergotrile, delfantrine, delmadinone acetate, delmetacin, delmopinol, delorazepam, deloxone, delprostenate, dembrexine, demecarium bromide, demeclocycline, demecolcine, demecycline, demegestone, demelverine, demexiptiline, democonazole, demoxepam, denaverine, denbufylline, denipride, denopamine, denpidazone, denzimol, deoxyspergualin, depramine, deprodone, deprostil, deptropine, derpanicate, desacetylcolchicine tartrate, desaspidin, desiclovir, descinolone acetonide, deserpidine, desipramine, deslanoside, desmethylcolchicine, desmethylmisonidazole, desmethylmoramide, desocriptine, desogestrel, desomorphine, desonide, desoximetasone, desoxycorticosterone acetate, desoxycorticosterone pivalate, desoxypyridoxine, detajmium bitartrate, detanosal, deterenol, detomidine, detorubicin, detrothronine, devapamil, dexamethasone, dexamethasone acefurate, dexamethasone acetate, dexamethasone dipropionate, dexamethasone phosphate, dexamisole, dexbrompheniramine, dexchlorpheniramine, dexclamol, dexetimide, dexetozoline, dexfenfluramine, deximafen, dexindoprofen, dexivacaine, dexlofexidine, dexmedetomidine, dexoxadrol, dexpanthenol, dexpropranolol, dexproxibutene, dexecoverine, dextilidine, dextroamphetamine, dextrofemine, dextromethorphan, dextromoramide, dextrorphan, dextrothyroxine, dezaguanine, dezocine, diacerein, diacetamate, diacetolol, diacetylmorphine, diamfenetide, diaminomethylphenazinium chloride, diamocaine, diampromide, diamthazole, dianhydrogalactitol, diapamide, diarbarone, diathymosulfone, diatrizoic acid, diaveridine, diazepam, diaziquone, diazoacetylglycine hydrazide, diazouracil, diazoxide, dibekacin, dibemethine, dibenamine, dibenzepin, dibrompropamidine, dibromsalan, dibrospidium chloride, dibucaine, dibuprol, dibupyrone, dibusadol, dicarbine, dicarfen, dichlorallyl lawsone, dichlorisone acetate, dichlormezanone, dichlorofluormethane, dichlorom,ethotrexate, dichlorophen, dichlorophenarsine, dichlorotetrafluoroethane, dichloroxylenol, dichlorphenamide, dichlorvos, diciferron, dicirenone, diclazuril, diclofenac, diclofensine, diclofurime, diclometide, diclonixin, dicloxacillin, dicobalt edetate, dicolinium iodide, dicresulene, dicumarol, dicyclomine, didemnin, dideoxycytidine, didrovaltrate, dieldrin, dienestrol, dienogest, diethadione, diethazine, diethylpropion, diethylstilbestrol, diethylstilbestrol diphosphate, diethylstilbestrol dipropionate, diethylthiambutene, diethyltoluamide, dietifen, difebarbamate, difemerine, difemetorex, difenamizole, difencloxazine, difenoximide, difenoxin, difetarsone, difeterol, diflorasone diacetate, difloxacin, difluanine, diflucortolone, diflurcortolone pivalate, diflumidone, diflunisal, difluprednate, diftalone, digalloyl trioleate, digitoxin, digoxin, dihexyverine, dihydralazine, dihydroazacytidine, dihydroergotamine, dihydrolenperone, dihydrostreptomycin, dihydrotachysterol, dihydroxyfluoroprogestrone, diisopromine, diisopropanolamine, dilazep, dilevalol, dilmefone, diloxanide, diltiazem, dimabefylline, dimecamine, dimecolonium iodide, dimecrotic acid, dimefadane, dimefline, dimelazine, dimemorfan, dimenhydrinate, dimenoxadol, dimeheptanol, dimepranol, dimepregnen, dimeprozan, dimercaprol, dimesna, dimesone, dimetacrine, dimetamfetamine, dimethadione, dimethaminostyrylquinoline, dimethazan, dimethindene, dimethiodal, dimethisoquin, dimethisterone, dimetholizine, dimethoxanate, dimethylhydroxytestosterone, dimethylnorandrostadienone, dimethylnortestosterone, dimethylstilbestrol, dimethyl, dimethylthiambutene, dimethyltubocurarinium chloride, dimetipirium bromide, dimetofrine, dimetridazole, diminazene, dimoxamine, dimoxaprost, dimoxyline, dimpylate, dinaline, dinazafone, diniprofylline, dinitolmide, dinoprost, dinoprostone, dinsed, diosmin, dioxadilol, dioxadrol, dioxamate, dioxaphetyl butyrate, dioxethedrin, dioxifedrine, dioxybenzone, dipenine bromide, diperodon, diphemanil methylsulfate, diphenadione, diphenan, diphenhydramine, diphendiol, diphenoxylate, diphenylpraline, diphoxazide, dipipanone, dipipoverine, dipiverin, diprafenone, diprenorphine, diprobutine, diprofene, diprogulic acid, diproleandomycin, diproqualone, diproteverine, diprotriozate, diproxadol, dipyridamole, dipyrithione, dipyrocetyl, dipyrone, dirithromycin, disobutamide, disofenin, disogluside, disopyramide, disoxaril, distigmine bromide, disulergine, disulfamide, disulfiram, disuprazole, ditazole, ditercalinium chloride, dithiazanine iodide, ditiocarb, ditiomustine, ditolamide, ditophal, divabuterol, dixanthogen, dizatrifone, dizocilpine, dobupride, dobutamine, docarpamine, doconazole, docusate, doliracetam, domazoline, domiodol, domiphen bromide, domipizone, domoprednate, domoxin, domperidone, don, donetidine, dopamantine, dopamine, dopexamine, dopropidil, doqualast, dorastine, doreptide, dosergoside, dotarizine, dotefonium bromide, dothiepin, doxacurium chloride, doxaminol, doxapram, doxaprost, doxazosin, doxefazepam, doxenitoin, doxepin, doxibetasol, doxifluridine, doxofylline, doxorubicin, doxpicomine, doxycycline, doxylamine, dramedilol, draquinolol, deazidox, dribendazole, drindene, drobuline, drocinonide, droclidinium bromide, drocode, drofenine, droloxifene, drometrizole, dromostanolone, dromostanolone propionate, dronabinol, dropempine, droperidol, droprenilamine, dropropizine, drotaverine, drotebanol, droxacin, droxicainide, droxicam, droxidopa, droxypropine, dulofibrate, dulozafone, duometacin, duoperone, dupracetam, durapatite, dyclonine, dydrogesterone, dymanthine, dyphylline, ebastine, ebrotidine, ebselen, ecastolol, echinomycin, echothiophate iodide, ecipramidil, eclanamine, eclazolast, econazole, ectylurea, edelfosine, edetic acid, edetol, edifolone, edogestrone, edoxudine, edrophonicum chloride, efaroxan, efetozole, eflornithine, efloxate, efrotomycin, elantrine, elanzepine, elderfield""s pyrimidine mustard, elfazepam, ellagic acid, elliptinium acetate, elmustine, elnadipine, eltenac, eltoprazine, elucaine, elziverine, embramine, embutramide, emepronium bromide, emetine, emiglitate, emilium tosylate, emopanil, emorfazone, emylcamate, enalapril, enalaprilat, enbucrilate, encainide; enciprazine, enclomiphene, encyprate, endomide, endralazine, endrysone, enefexine, enestebol, enfenamic acid, enflurane, eniclobrate, enilconazole, enilospirone, enisoprost, enocitabine, enolicam, enoxacin, enoxamast, enoximone, enoxolone, eniprazole, eniproline, enprazepine, enprofylline, enpromate, enprostil, enrofloxacin, entsufon sodium, enviomycin, enviradene, epalretat, epanolol, eperisone, ephedrine, epicainide, epicillin, epicriptine, epiestriol, epimestrol, epinastine, epinephrine, epinephryl borate, epipropidine, epirizole, epiroprim, epirubicin, epithiazide, epitiostanol, epoprostenol, epostane, eprazinone, eprovafen, eproxindine, eprozinol, epsiprantel, eptaloprost, eptazocine, equilin, erdosteine, ergocalciferol, ergoloid mesylates, ergonovine, ergosterol, ergotamine, ericolol, erizepine, erocainide, erythrityl tetranitrate, erythromycin, erythromycin acistrate, erythromycin ethylsuccinate, erythromycin propionate, erythrosine, esaprazole, esculamine, eseridine, esflurbiprofen, esmolol, esorubicin, esproquin, estazolam, estradiol, estradiol benzoate, estradiol cypionate, estradiol dipropionate, estradiol enanthate, estradiol undecylate, estradiol valerate, estramustine, estramustine phosphate, estrapronicate, estrazinol, estriol, estrofurate, estrone, estrone hydrogen sulfate, estropipate, esuprone, etabenzarone, etacepride, etafedrine, etafenone, etamestrol, etamiline, etamiphyllin, etamocycline, etanidazole, etanterol, etaqualone, etasuline, etazepine, etazolate, etebenecid, eterobarb, etersalate, ethacridine, ethacrynic acid, ethambutol, ethamivan, ethamsylate, ethanolamine oleate, ethaverine, ethchlorvynol, ethenzamide, ethazide, ethidium chloride, ethinamate, ethinyl estradiol, ethiofos, ethionamide, ethsterone, ethoheptazine, ethomoxane, ethonam, ethopropazine, ethosuximide, ethotoin, ethoxazene, ethoxazorutoside, ethoxzolamide, ethyybenztropine, ethyl biscoumacetate, ethyl carfluzepate, ethyl cartrizoate, ethyl dibunate, ethyl dirazepate, ethylenediamine, ethylestrenol, ethylhydrocupreine, ethyl loflazepate, ethylmethylthiambutene, ethylmorphine, 9-ethyl-6-mercaptopurine, ethyl nitrite, ethylnorepinephrine, ethylparaben, ethylphenacemide, ethylstibamine, ethynerone, ethynodiol diacetate, ethypicone, etibendazole, eticlopride, eticyclidine, etidocaine, etidronic acid, etifelmine, etifenin, etifoxine, etilamfetamine, etilefrine, etilefrine pivalate, etintidine, etiochlanolone, etipirium iodide, etiproston, etiracetam, etiroxate, etisazole, etisomicin, etisulergine, etizolam, etocarlide, etocrylene, etodolac, etodroxzine, etofamide, etofenamate, etofenprox, etofibrate, etoformin, etofuradine, etofylline, etoglucid, etolorex, etolotifen, etoloxamine, etomidate, etomidoline, etomoxir, etonitazene, etoperidone, etoposide, etoprindole, etoprine, etorphine, etosalamide, etoxadrol, etoxeridine, etozolin, etrabamine, etretinate, etryptamine, etymemazine, eucalyptol, eucatropine, eugenol, euprocin, evandamine, Evans blue, exalamide, exametazine, exaprolol, exepanol, exifone, exiproben, falintolol, falipamil, famiraprinium chloride, famotidine, famotine, famiprofazone, fanetizole, fantridone, fazadinium bromide, fazaribine, febantel, febarbamate, februpol, febuverine, feclemine, feclobuzone, fedrilate, felbamate, felbinac, felipyrine, felodipine, femoxetine, fenabutene, fenacetinol, fenaclon, fenadiazole, fenaptic acid, fenalamide, fenalcomine, fenamifuril, penamole, fenaperone, fenbendazole, fenbencillin, fenbufen, fenbutrazate, fencamfamine, fencibutirol, fenclexonium metilsulfate, fenclofenac, fenclonine, fenclorac, fenlozic acid, fendiline, fendosal, feneritrol, fenestrel, fenethazine, fenethylline, fenetradil, fenflumizole, fenfluramine, fenfluthrin, fengabine, fenharmane, fenimide, feniodium chloride, fenipentol, fenirofibrate, fenisorex, fenmetozole, fenmetramide, fenobam, fenocinol, fenoctimine, fenofibrate, fenoldopam, fenoprofen, fenoterol, fenoverine, fenoxazoline, fenoxedil, fenozolone, fenpentadiol, fenperate, fenipalone, fenipramide, feniprane, fenpiverinium bromide, fenprinast, fenproporex, fenprostalene, fenquizone, fenretinide, fenspiride, fentanyl, fentiazac, fenticlor, fenticonazole, fentonium bromide, fenyripol, fepentolic acid, fepitrizol, fepradinol, feprazone, fepromide, feprosidnine, ferriclate calcium, ferrotrenine, ferrous fumarate, ferrous gluconate, fetoxylate, fexicaine, fexinidazole, fezatione, fezolamine, fiacitabine, fibracillin, filenadol, filipin, fifexide, flamenol, flavamine, flavodic acid, flavodil, flavoneactic acid, flavoxate, flazalone, flecainide, flerobuterol, fleroxacin, flesinoxan, flestolol, fletazepam, floctafenine, flomoxef, flopropione, florantyrone, flordipine, floredil, florfenicol, florifenine, flosequinan, flotrenizine, floverine, floxacillin, floxacrine, floxuridine, fluacizine, flualamide, fluanisone, fluazacort, flubanilate, flubendazole, flubepride, flucabril, flucetorex, flucindole, fluciprazine, flucloronide, fluconazole, flucrylate, flucytosine, fludalanine, fludarabine phosphate, fludazonium chloride, fludiazepam, fludorex, fludoxopone, fludrocortisone acetate, flufenamic acid, flufenisal, flufosal, flufylline, fluindarol, fluindione, flumazenil, flumecinol, flumedroxone-17-acetate, flumequine, flumeridone, flumethasone, flumethasone pivalate,flumethiazide, flumetramide, flumexadol, flumezapine, fluminorex, flumizole, flumoxonide, flunamine, flunarizine, flunidazole, flunisolide, flunisolide acetate, flunitrazepan, flunixin, flunoprost, flunoxaprofen, fluocinolone acetonide, fluocinonide, flourcortin butyrate, fluocortolone, fluocortolone caproate, fluorescein, fluoresone, fluoroadenosine, 3-fluoroandrostanol, fluorodopane, fluorohydroxyandrosterone, fluorometholone, fluorometholone acetate, fluorosalan, 6-fluorotestosterone propionate, fluorouracil, 9-fluoroxotestenololactone, 9-fluoroxotestololacetone, fluotracen, fluqxetine, fluoxymesterone, fluparoxan, flupentixol, fluperamide, fluperlapine, fluperolone acetate, fluphenazine, fluphenazine enanthate, flupimazine, flupirtine, flupranone, fluprazine, fluprednidene, fluprednisolone, fluprednisolone valerate, fluprofen, fluprofylline, fluproquazone, fluprostenol, fluquazone, fluradoline, flurandrenoline, flurantel, flurazepam, flurbiprofen, fluretofen, flurithromycin, flurocitabine, flurofamide, flurogestone acetate, flurothyl, fluroxene, flusoxolol, fluspiperone, fluspirilene, flutamide, flutazolam, flutemazepam, flutiazin, fluticasone propionate, flutizenol, flutonidine, flutoprazepam, flutroline, flutropium bromide, fluvoxamine, fluzinamide, fluzoperine, folescutol, folic acid, fomidacillin, fominoben, fomocaine, fonazine, fopirtoline, forfenimex, formebolone, formetorex, formintrazole, formocortal, formoterol, fosarilate, fosazepam, foscarnet, foscolic acid, fosenazide, fosfocreatine, fosfomycin, fosfonet, fosfosal, fosinapril, fosmenic acid, fosmidomycin, forpirate, fostedil, fostriecin, fotemustine, fotreamine, frabuprofen, frentizole, fronepidil, froxiprost, ftaxilide, ftivazide, ftorafur, ftormetazine, ftorpropazine, fubrogonium iodide, fuchsin, fumagillin, fumoxcillin, fuprazole, furacrinic acid, furafylline, furalazine, furaltadone, furaprofen, furazabol, furazolidone, furazolium chloride, furbucillin, furcloprofen, furegrelate, furethidine, furfenorex, furidarone, furmethoxadone, furobufen, furodazole, furofenac, furomazine, furosemide, furostilbestrol, fursalan, fursultiamine, furterene, furtrethonium iodide, fusidic acid, fuzlocillin, gabapentin, gabexate, gaboxadol, galantamine, gallamine triethodide, gallopamil, galosemide, galtifenin, gampexine, gamolenic acid, ganciclovir, ganglefene, gapicomine, gapromidine, gefarnate, gemazocine, gemcadiol, gemeprost, gemfibrozil, gentamicin, gentian violet, gepefrine, gepirone, geroquinol, gestaclone, gestadienol, gestodene, gestonorone caproate, gestrinone, giparmen, gitaloxin, gitoformate, glafenine, glaziovine, gliamilide, glibornuride, glibutimine, glicaramide, glicetanile,geroquinol, gestaclone, gestadienol, gestodene, gestonorone caproate, gestrinone, giparmen, gitaloxin, gitoformate, glafenine, glaziovine, gliamilide, glibornuride, glibutimine, glicaramide, glicetanile, gliclazide, glicondamide, glidazamide, gliflumide, glimepiride, glipentide, glipizide, gliquidone, glisamuride, glisindamide, glisolamide, glisoxepide, gloxazone, gloximonam, glucametacin, glucosamine, glucosulfamide, glucosulfone, glucurolactone, glucuronamide, glunicate, glutamic acid, glutaral, glutarimide, glutaurine, glutethimide, glyburide, glybuthiazol, glybuzole, glyceryl monostearate, glycidyl methacrylate, glycine, glyclopyramide, glybiarsol, glycopyrrolate, glycyclamide, glyhexamide, glymidine, glyoctamide, glypinamide, glyprothiazol, glysobuzole, gold thiomalate, gold sodium thiosulfate, granisetron, griseofulvin, guabenxan, guacetisal, guafecainol, guaiactamine, guaiapate, guaietolin, guaifenesin, guaimesal, guaisteine, guaithylline, guamecycline, guanabenz, guanacline, guanadrel, guanazodine, guanazole, guanclofine, guancydine, guanethidine, guanfacine, guanisoquin, guanoclor, guanoctine, guanoxabenz, guanoxan, guanoxyfen, hadacidin, halazepam, halazone, halcinonide, halethazole, halocortolone, halofantrine, halofenate, halofuginone, halometasone, halonamine, halopemide, halopenium chloride, haloperidol, haloperidol decanoate, haloperidone acetate, haloprogesterone, haloprogin, halothane, haloxazolam, haloxon, halquinols, hedaquinium chloride, hepronicate, heptabarbital, heptaminol, heptaverine, heptolamide, hepzidine, hetacillin, hetaflur, heteronium bromide, hexachlorophene, hexacyclonate, hexacyprone, hexadiline, hexadimethrine bromide, hexafluorenium bromide, hexamethonium bromide, hexamidine, hexapradol, hexaprofen, hexapropymate, hexasonium iodide, hexacarbacholine bromide, hexedine, hexestrol, hexetidine, hexobarbital, hexobendine, hexocyclium methylsulfate, hexoprenaline, hexopyrronium bromide, hexylcaine, hexylene glycol, hexylresorcinol, histamine, histapyrrodine, homarylamine, homatropine, homatropine methylbromide, homidium bromide, homochlorcyclizine, homofenazine, homoharringtonine, homopipramol, homosalate, homotestosterone propionate, homprenorphine, hopantenic acid, hoquizil, hycanthone, hydracarbazine, hydralazine, hydrargaphen, hydrobentizide, hydrochlorthiazide, hydrocodone, hydrocortamate, hydrocortisone, hydrocortisone aceponate, hydrocortisone acetate, hydrocortisone butyrate, hydrocortisone cypionate, hydrocortisone-phosphate, hydrocortisone succinate, hydrocortisone valerate, hydroflumethiazide, hydromadinone, hydromorphinol, hydromorphone, hydroquinone, hydroxindasate, hydroxindasol, hydroxyoxocobalamin, hydroxy amphetamine, hydroxychloroquine, hydroxydimethandrostadienone, hydroxydione succinate, hydroxymethylandrostanone, 10-hydroxynorehisterone, hydroxypethidine, hydroxyphenamate, hydroxyprocaine, hydroxyprogeserone, hydroxyprogesterone caproate, hydroxypyridine tartrate, hydroxystilbamidine, 7-hydroxytestololacetone, hydroxytestosterone propionate, hydroxytetracaine, hydroxytoluic acid, hydroxyurea, hydroxyzine, hymecromone, hyoscyamine, hypericin, ibacitabine, ibafloxacin, ibazocine, ibopamine, ibrotamide, ibudilast, ibufenac, ibuprofen, ibuprofen piconol, ibuproxam, ibuterol, ibuverine, icazepam, icosipiramide, icotidine, idarubicin, idaverine, idazoxan, idebenone, idenast, idoxuridine, idralfidine, idrocilamide, idropranolol, ifenprodil, ifosfamide, ifoxetine, ilmofosine, iloprost, imafen, imanixil, imazodan, imcarbofos, imexon, imiclopazine, imidazole salicylate, imidazopyrazole, imidecyl iodine, imidocarb, imidoline, imidurea, imiloxan, iminophendimide, imipenem, imipramine, imipraminoxide, imirestat, imolamine, imoxiterol, impacarzine, impromidine, improsulfan, imuracetam, inaperisone, indacrinone, indalpine, indanazoline, indanidine, indanorex, indapamide, indatraline, indacainide, indeloxazine, indenolol, indicine-N-oxide, indigotindisulfonic acid, indobufen, indocate, indocyanine green, indolapril, indolidan, indomethacin, indopanolol, indopine, indoprofen, indoramin, indorenate, indoxole, indriline, inicarone, inocoterone, inosine, inosine dialdehyde, inositol niacinate, inproquone, intrazole, intriptyline, iobenzamic acid, iobutic acid, iocarmic acid, iocetamic acid, iodamide, iodecimol, iodetryl, iodipamide, iodixanol, iodoalphionic acid, iodol, iodophthalein, iodoquinol, iodothiouracil, iodoxamic acid, ioglicic acid, ioglucol, ioglucomide, ioglunide, ioglycamic acid, iogulamide, iohexol, iodlidonic acid, iolixanic acid, iomeglamic acid, iomeprol, iomorinic acid, iopamidol, iopanoic acid, iopentol, iophendylate, iophenoxic acid, ioprocemic acid, iopromide, iopronic acid, iopydol, iopydone, iosarcol, iosefamic acid, ioseric acid, iosimide, iosulamide, iosumetic acid, iotasul, iotetric acid, iothalamic acid, iotranic acid, iotrizoic acid, iotrolan, iotroxic acid, ioversol, ioxabrolic acid, ioxaglic acid, ioxitalamic acid, ioxotrizoic acid, iozomic acid, ipexidine, ipodic acid, ipragratine, ipramidil, ipratropium bromide, iprazochrome, ipriflavone, iprindole, iprocinodine, iproclozide, iprocrolol, iprofenin, iproheptine, iproniazid, iproidazole, iproplatin, iprotiazem, iproxamine, iprozilamine, ipsalazide, ipsapirone, iquindamine, irindalone, irloxacin, irolapride, irsogladine, isamfazone, isamoltan, isamoxole, isaxonine, isbogrel, isepamicin, isoaminile, isobromindione, isobucaine, isobutamben, isocarboxazid, isoconazole, isocromil, isoetharine, isofezolac, isoflupredone acetate, isoflurane, isoflurophate, isoleucine, isomazole, isomerol, isometamidium, isomethadone, isometheptene, isomylamine, isoniazid, isonixin, isoprazone, isoprednidene, isoprofen, isoprofamide iodide, isopropicillin, isopropyl myristate, isopropyl palmitate, isoproterenol, isosorbide, isosorbide dinitrate, isosorbide mononitrate, isospalglumic acid, isosulfan blue, isosulpride, isothipendyl, isotic, isotiquimide, isotretinoin, isoxaprolol, isoxepac, isoxicam, isoxsuprine, isradipine, itanoxone, itazigrel, itraconazole, itrocainide, ivermectin bib, ivoqualine, josamycin, kainic acid, kalafungin, kanamycin, kebuzone, keracyanin, ketamine, ketanserin, ketazocine, ketazolam, kethoxal, ketipramine, ketobemidone, ketocaine, ketocainol, ketoconazole, ketoprofen, ketorfanol, ketorolac, ketotifen, ketotrexate, khellin, khelloside, kitasamycin, labetalol, lacidipine, lactalfate, lactose, lactulose, lamotrigine, lamtidine, lanatoside, lapachol, lapinone, lapyrium chloride, lasalocid, laudexium methyl sulfate, lauralkonium chloride, laureth, laurixamine, laurocapram, lauroguadine, laurolinium acetate, lauryl isoquinolinium, lefetamine, leflunomide, leiopyrrole, lemidosul, lenampicillin, leniquinsin, lenperone, leptacline, lergotrile, letimide, letosteine, leucine, leucinocaine, leucocianidol, leucovorin, levacecarnine, levallorphan, levamfetamine, levamisole, levdropropizine, levisoprenaline, levlofexidine, levobunolol, levocabastine, levocarnitine, levodopa, levofacetoperane, levofenfluramine, levofuraltadone, levoglutamide, levomenol, levomethadone, levomethadyl acetate, levomethorphan, levometiomeprazine, levomopranol, levomoramide, levonantradol, levonordeprin, levonorgestrel, levophenacyl morphan, levopropoxyphene, levopropylcillin, levopropylhexedrine, levoprotiline, levorin, levorphanol, levothyroxine, levoxadrol, lexofenac, libecillide, libenzapril, lidamidine, lidocaine, lidofenin, lidoflazine, lifibrate, lilopristone, limaprost, lincomycin, lindane, linsidomine, iothyronine, liroldine, lisinopril, lisuride, lithium carbonate, lithium citrate, litracen, lividomycin, lixazinone, lobeline, lobendazole, lobenzarit, lobuprofen, locicortone, lodaxaprine, lodacezarlodinixil, lodiperone, lodoxamide, lodoxamide ethyl, lofemizole, lofendazam, lofentanil, lofepramine, lofexidine, loflucarban, lombazole, lomefloxacin, lometraline, lomevactone, lomifylline, lomofungin, lomustine, lonapalene,lonaprofen, lonazolac, lonidamine, loperamide, loperamide oxide, lopirazepam, loprazolam, loprodiol, lorajmine, lorapride, loratadine, lorazepam, lorbamate, lorcainide, lorcinadol, lorglumide, lormetazepam, lortalamine, lorzafone, losindole, losulazine, lotifazole, lotrifen, lotucaine, lovastatin, loxanast, loxapine, loxiglumide, loxoprofen, loxtidine, lozilurea, lucanthone, lucartamide, lucimycin, lufuradom, lupitidine, luprostiol, luxabendazole, lyapolate sodium, lycetamine, lydimycin, lymecycline, lynestrenol, lysergide, lysine, mabuterol, maduramicin, mafenide, mafoprazine, mafosfamide, magnesium citrate, magnesium gluconate, magnesium salicylate, malathion, malethamer, malic acid, malotilate, manidipine, manganese gluconate, mannitol, mannitol hexanitrate, mannomustine, mannosulfan, manozodil, maprotiline, maridomycin, mariptiline, maroxepin, maytansine, mazaticol, mazindol, mazipredone, mebanazine, mebendazole, mebenoside, mebeverine, mebezonium iodide, mebhydrolin, mebiquine, mebolazine, mebrofenin, mebutamate, mebutizide, mecamylamine, mecarbinate, mecetronium ethylsulfate, mechlorethamine, meciadanol, mecinarone, meclizine, meclocycline, meclocycline sulfosalicylate, meclofenamic acid, meclofenoxate, meclonazepam, mecloqualone, mecloralurea, meclorisone dibutyrate, mecloxamine, mecobalamin, mecrylate, mecysteine, medazepam, medazomide, medetomidine, medibazine, medifoxamine, medorinone, medorubicin, medrogestone, medronic acid, medroxalol, medroxyprogestrone, medroxyprogestrone acetate, medrylamine, medrysone, mefeclorazine, mefenamic acid, mefenidil, mefenidramium metilsulfate, mefenorex, mefeserpine, mefexamide, mefloquine, mefruside, megalomicin, megestrol acetate, meglitinide, megucycline, meglumine, meglutol, meladrazine, melarsonyl, melarsoprol, melengestrol acetate, meletimide, melinamide, melitracen, melizame, meloxicam, melperone, melphalan, memantine, memotine, menabitan, menadiol, menadiol diphosphate, menadiol disulfate, menadione, menadione sodium bisulfite, menatetrenone, menbutone; menfegol, menglytate, menitrazepam, menoctone, menogaril, menthol, meobentine, meparfynol, mepazine, mepenzolate bromide, meperidine, mephenesin, mephenoxalone, mephentermine, mephenyton, mephobarbital, mepindolol, mepiprazole, mepiroxol, mepitiostane, mepivacaine, mepixanox, mepramidil, meprednisone, meprobamate, meproscillarin, meproxitol, meprylcaine, meptazinol, mequidox, mequinol, mequitazine, meralein, meralluride, merbarone, merbromin, mercaptamine, mercaptomerin, mercaptopurine, mercuderamide, mercufenol chloride, mercumatilin, mercurobutol, mergocriptine, merophan, mersalyl, mesabolone, mesalamine, meseclazone, mesna, mesocarb, meso-hexestrol, mesoridazine, mesipirenone, mestanolone, mesterolone, mestranol, mesudipine, mesulergine, mesulfamide, mesulfen, mesuprine; metabromsalan, metacetamol, metaclazepam, metaglycodol, metahexamide, metamelfalan, metamfazone, metamfepramone, metampicillin, metanixin, metapramine, metaproterenol, metaraminol, metaterol, metaxalone, metazamide, metazide, metazocine, metbufen, meteneprost, metergoline, metergotamine, metescufylline, metesculetol, metethoheptazine, metformin, methacholine chloride, methacycline, methadone, methadyl acetate, methallenestril, methallibure, methalthiazide, methamphetamine, methandriol, methandrostenolone, methaniazide, methantheline bromide, methaphenilene, methapyrilene, methaqualone, metharbital, methastyridone, methazolamide, methdilazine, methenamine, methenolone acetate, methenolone enanthate, metheptazine, methestrol, methetoin, methicillin, methimazole, methiodal sodium, methioguanine, methiomeprazine, methionine, methisazone, methitural, methixene, methocarbamol, methohexital, methopholine, methoserpidine, methotrexate, methotrimeprazine, methoxamine, methoxsalen, methoxyflurane, methoxyphedrine, methoxyphenamine, methoxypromazine, methscopolamine bromide, methsuximide, methyllothiazide, N-methyladrealone hcl, methyl alcohol, methylatropine nitrate, methylbenactyzium bromide, methylbenzethonium, methylchromone, methyldesorphine, methyldihydromorphine, methyldopa, methyldopate, methylene blue, methylphedrine, methylergonovine, methylformamide, methyl nicotinate, 2-methyl-19-nortestosterone, 2-methyl-11-oxoprogestrone, methyl palmoxirate, methylparaben, methylphendiate, methylprednisolone, methylprednisolone aceponate, methylprednisolone acetate, methylprednisolone hemisuccinate, methylprednisolone phosphate, methylprednisolone suleptanate, methyl salicylate, methylstreptonigrin, 4-methyltestosterone, 7-methyltestosterone, 17-methyltestosterone, 7-methyltesosterone propionate, methylthionosine, 16-methylthioprogestone, methylthiouracil, methynodiol diacetate, methyprylon, methysergide, metiamide, metiapine, metiazinic acid, metibride, meticrane, metildigoxin, metindizate, metioprim, metioxate, metipirox, metipranolol, metiprenaline, metitepine, metizoline, metkephamid, metochalcone, metocinium iodide, metoclopramide, metocurine iodide; metofenazate, metogest, metolazone, metomidate, metopimazine, metopon, metoprine, metoprolol, metoquizine, metoserpate, metostilenol, metoxepin, metrafazoline, metralindole, metrazifone, metrenperone, metribolone, metrifonate, metrifudil, metrizamide, metrizoic acid, metronidazole, meturedepa, metyrapone, metyridine, metyrosine, mevastatin, mexafylline, mexazolam, mexenone, mexiletine, mexiprostil, mexoprofen, mexrenoate, mezacopride, mezepine, mezilamine, mezlocillin, mianserin, mibolerone, micinicate, miconazole, micronomicin, midaflur, midaglizole, midalcipran, midamaline, midazogrel, midazolam, midecamycin, midodrine, mifentidine, mifepristone, mifobate, miglitol, mikamycin, milacemide, milenperone, milipertine, miloxacin, milrinone, milverine, mimbane, minaprine, minaxolone, mindolilol, mindoperone, minepentate, minocromil, minocycline, minoxidil, mioflazine, mipimazole, mirincamycin, miristalkonium chloride, miroprofen, mirosamicin, misonidazole, misoprostol, mitindomide, mitobronitol, mitoclomine, mitoguazone, mitolactol, mitomycin, mitonafide, mitopodozide, mitoquidone, mitotane, mitotenamine, mitoxantrone, mitozolomide, mivacurium chloride, mixidine, misoprostol, mitindomide, mitobronitol, mitoclomine, mitoguazone, mitolactol, mitomycin, mitonafide, mitopodozide, mitoquidone, mitotane, mitotenamine, mitoxantrone, mitozolomide, mivacurium chloride, mixidine, mizoribine, mobecarb, mobenzoxamine, mocimycin, mociprazine, moclobemide, moctamide, modafinil, modaline, mofebutazone, mofloverine, mofoxime, molfarnate, molinazone, molindone, molracetam, molsidomine, mometasone furoate, monalazone disodium, monensin, monobenzone, monoethanolamine, monometacrine, monophosphothiamine, monothioglycerol, monoxerutin, montirelin, moperone, mopidamol, mopidralazine, moprolol, moquizone, morantel, morazone, morclofone, morforex, moricizine, morinamide, morniflumate, morocromen, moroxydine, morpheridine, morphine, morsuximide, motapizone, motrazepam, motretinide, moveltipril, moxadolen, moxalactam, moxaprindine, moxastine, moxaverine, moxazocine, moxestrol, moxicoumone, moxipraquine, moxisylyte, moxnidazole, moxonidine, mupirocin, murabutide, murocainide, muzolimine, mycophenolic acid, myfadol, myralact, myrophine, myrtecaine, nabazenil, nabilone, nabitan, naboctate, nabumetone, nadide, nadolol, nadoxolol, naepaine, nafamostat, nafazatrom, nafcaproic acid, nafcillin, nafenodone, nafenopin, nafetolol, nafimidone, nafiverine, naflocort, nafomine,nafoxadol, nafoxidine, nafronyl, naftalofos, naftazone, naftifine, naftopidil, naftoxate, naftypramide, nalbuphine, nalidixic acid, nalmefene, nalmexone, nalorphine, naltrexone, naminterol, namoxyrate, nanaprocin, nandrolone cyclotate, nandrolone decanoate, nandrolone phenpropionate, nanofin, nantradol, napactadine, napamezole, naphazoline, naphthonone, naprodoxime, naproxen, naproxol, naranol, narasin, natamycin, naxagolide, naxaprostene, nealbarbital, nebidrazine, nebivolol, nebracetam, nedocromil, nefazodone, neflumozide, nefopam, nelezaprine, neoarsphenamine, neocinchophen, neomycin, neostigmine bromide, nequinate, neraminol, nerbacadol, nesapidil, nesosteine, netilmicin, netobimin, neutramycin, nexeridine, niacin, niacinamide, nialamide, niaprazine, nibroxane, nicafenine, nicainoprol, nicametate, nicarbazin, nicarpidine, nicergoline, niceritrol, niceverine, niclofolan, niclosamide, nicoboxil, nicoclonate, nicocodine, nicocortonide, nicodicodine, nicofibrate, nicofuranose, nicofurate, nicogrelate, nicomol, nicomorphine, nicopholine, nicorandil, nicothiazone, nicotinyl alcohol, nicoxamat, nictiazem, nictindole, nodroxyzone, nifedipine, nifenalol, nifenazone, niflumic acid, nifluridide, nifuradene, nifuraldezone, nifuralide, nifuratel, nifuratrone, nifurdazil, nifurethazone, nifurfoline, nifurimide, nifurizone, nifurmazole, nifurmerone, nifuroquine, nifuroxazide, nifuroxime, nifurpipone, nifurpirinol, nifurprazine, nifurquinazole, nifursemizone, nifursol, nifurthiazole, nifurtimox, nifurtoinol, nifurvidine, nifurzide, niguldipine, nihydrazone, nikethamide, nileprost, nilprazole, niludipine, nilutamide, nilvadipine, nimazone, nimesulide, nimetazepam, nimidane, nimodipine, nimorazole, nimustine, niometacin, niperotidine, nipradilol, niprofazone, niridazole, nisbuterol, nisobamate, nisoldipine, nisoxetine, nisterime acetate, nitarsone, nitazoxanide, nithiamide, nitracrine, nitrafudam, nitralamine, nitramisole, nitraquazone, nitrazepam, nitrefazole, nitrendipine, nitricholine, nitrochlofene, nitrocycline, nitrodan, nitrofurantoin, nitrofurazone, nitroglycerin, nitromersol, nitromide, nitromifene, nitroscanate, nitrosulfathiazole, nitroxinil, nitroxoline, nivazol, nivimeldone, nixylic acid, nizatidine, nizofenone, noberastine, nocloprost, nocodazole, nofecainide, nogalamycin, nolinium bromide, nomegestrol, nomelidine, nomifensine, nonabine, nonaperone, nonapyrimine, nonoxynol-4, nonoxynol-9, noracymethadol, norbolethone, norbudrine, norclostebol, norcodeine, nordazepam, nordefrin, nordinone, norepinephrine, norethandrolone, norethindrone, norethindrone acetate, norethynodrel, noreximide, norfenefrine, norfloxacin, norfloxacin succinil, norflurane, norgesterone, norgestimate, norgestomet, norgestrel, norgestrienone, norletimol, norlevorphanol, normethadone, normethandrone, normorphine, norpipanone, nortestosterone propionate, nortetrazepam, nortriptyline, norvinisterone, nosantine, noscapine, nosiheptide, novobiocin, noxiptiline, noxytiolin, nuclomedone, nuclotixine, nufenoxole, nuvenzepine, nylestriol, nylidrin, nystatin, obidoxime, ociltide, ocrylate, octabenzone, octacaine, octafonium chloride, octamoxin, octamylamine, octanoic acid, octapinol, octastine, octaverine, octazamide, octenidine, octenidine saccharin, octicizer, octimibate, octorylene, octodrine, octopamine, octotiamine, octoxynol-9, octriptyline, octrizole, ofloxacin, ofornine, oftasceine, olaflur, olaquindox, oleanomycin, oletimol, oleyl alcohol, olivomycin a, olmidine, olpimedone, olsalazine, oltipraz, olvanil, omeprazole, omidoline, omoconazole, omonasteine, onapristone, ondansetron, ontianil, opiniazide, opipramol, orazamide, orbutopril, orconazole, orestrate, ormetoprim, ornidazole, ornipressin, ornithine, ornoprostil, orotic acid, orotirelin, orpanoxin, orphenadrine, ortetamine, osalmid, osmadizone, otilonium bromide, otimerate sodium, ouabain, oxabolone cipionate, oxabrexine, oxaceprol, oxacillin, oxadimedine, oxaflozane, oxaflumazine, oxagrelate, oxalinast, oxaliplatin, oxamarin, oxametacin, oxamisole, oxamniquine, oxanamide, oxandrolone, oxantel, oxapadol, oxapium iodide, oxapropanium iodide, oxaprotiline, oxaprozin, oxarbazole, oxatomide, oxazafone, oxazepam, oxazidione, oxazolam, oxazorone, oxcarbazepine, oxdralazine, oxeladin, oxendolone, oxepinac, oxetacillin, oxethazaine, oxetorone, oxfendazole, oxfenicine, oxibendazole, oxibetaine, oxiconazole, oxidopamine, oxidronic acid, oxifentorex, oxifungin, oxilorphan, oximonam, oxindanac, oxiniacic acid, oxiperomide, oxiracetam, oxiramide, oxisopred, oxisuran, oxitefonium bromide, oxitriptan, oxitriptyline, oxitropium bromide, oxmetidine, oxodipine, oxogestone phenpropionate, oxolamine, oxolinic acid, oxomemazine, oxonazine, oxophenarsine, oxoprostol, oxpheneridine, oxprenoate potassium, oxprenolol, oxtriphylline, oxybenzone, oxybutynin, oxychlorosene, oxycinchophen, oxyclozanide, oxycodone, oxydipentonium chloride, oxyfedrine, oxymesterone, oxymetazoline, oxymetholone, oxymorphone, oxypendyl, oxypertine, oxyphenbutazone, oxyphenonium bromide, oxypurinol, oxypyrronium bromide, oxyquinoline, oxyridazine, oxysonium iodide, oxytetracycline, oxytiocin, ozagrel, ozolinone, pacrinolol, pactamycin, padimate, pafenolol, palatrigine, paldimycin, palmidrol, palmoxiric acid, pamabrom, pamaquine, pamatolol, pamidronic acid, pancuronium bromide, panidazole, panomifene, patenicate, panthenol, pantothenic acid, panuramine, papaverine, papaveroline, parachlorophenol, paraflutizide, paraldehyde, paramethadione, paramethasone acetate, paranyline, parapenzolate bromide, parapropamol, pararosaniline, pararosaniline embonate, paraxazone, parbendazole, parconazole, pareptide, parethoxycaine, pargeverine, pargolol, pargyline, paridocaine, parodilol, paromomycin, paroxetine, paroxypropione, parsalmide, partricin, parvaquone, pasiniazid, paulomycin, paxamate, pazelliptine, pazoxide, pcnu, pecilocin, pecocycline, pefloxacin, pelanserin, pelretin, pelrinone, pemedolac, pemerid, pemoline, pempidine, penamecillin, penbutolol, pendecamaine, penfluridol, penflutizide, pengitoxin, penicillamine, penicillin procaine, penicillin, penimepicycline, penimocycline,.penirolol, penmesterol, penoctonium bromide, penprostene, pentabamate, pentacynium chloride, pentaerythritol tetranitrate, pentafluranol, pentagastrin, pentagestrone, pentalamide, pentamethonium bromide, pentamethylmelamine, pentamidine, pentamoxane, pentamustine, pentapiperide, pentapiperium methylsulfate, pentaquine, pentazocine, pentetate calcium trisodium, pentetic acid, penthienate bromide, penthrichloral, pentiapine maleate, pentifylline, pentigetide, pentisomicin, pentisomide, pentizidone, pentobarbital, pentolinium tartrate, pentomone, pentopril, pentorex, pentosan polysulfate sodium, pentostatin, pentoxifylline, pentrinitrol, pentylenetrazole, peplomycin, pepstatin, peraclopone, peradoxime, perafensine, peralopride, peraquinsin, perastine, peratizole, perbufylline, perfluamine, perflunafene, pergolide, perhexilene, periciazine, perimetazine, perindopril, perindoprilat, perisoxal, perlapine, permethrin, perphenazine, persilic acid, petrichloral, pexantel, phanquone, phenacaine, phenacemide, phenacetin, phenacttropinium chloride, phenadoxone, phenaglycodol, phenamazoline, phenampromide, phenarsone sulfoxylate, phenazocine, phenazopyridine, phencarbamide, phencyclidine, phendimetrazine, phenelzine, pheneridine, phenesterin, penethicillin, phenformin, phenglutarimide, phenicarbazide, phenindamine, phenindione, pheniprazine, pheniraminie, phenisonone, phenmetrazine, phenobarbital, phenobutiodil, phenolphtalein, phenolsulfonphthalein, phenomorphan, phenoperidine, phenothiazine, phenothrin, phenoxybenzamine, phenoxypropazine, phenprobamate, phenprocoumon, phenpromethamine, phensuximide, phentermine, phentolamine, phenylalanine, phenyl aminosalicylate, phenylbutazone, phenylrphrine, phenylethyl alcohol, phenylmercuric acetate, phenylmercuric borate, phenylmercuric chloride, phenylmercuric nitrate, phenylmethylbarbituric acid, phenylpropanolamine, phenylthilqne, phenyltoloxamine, phenyramidol, phenytoin, phethafbital, pholcodine, pholedrine, phosphoramide mustard, phoxim, phthalofyne, phthalysulfacetamide, phthalylsulfamethizole, phthalylsulfathiazole, physostigmine, phytic acid, phytonadiol diphosphate, phytonadione, pibecarb, pibenzimol, pibecarb, pibenzimol, piberaline, picafibrate, picartamide, picenadol, picilorex, piclonidine, piclopastine, picloxydine, picobenzide, picodralazine, picolamine, piconol, picoperine, picoprazole, picotamide, picotrin diolamine, picumast, pidolic acid, pifarnine, pifenate, pifexole, piflutixole, pifoxime, piketoprofen, pildralazine, pilocarpine, pimoclone, pimefylline, pimelautde, pimetacin, pimethixene, pimetine, pimetremide, piminodine, pimobendan, pimondiazole, pimozide, pinacidil, pinadoline, pinafide, pinaverium bromide, pinazepam, pincainide, pindolol, pinolcaine, pinoxepin, pioglitazone, pipacycline, pipamazine, pipaperone, pipazethate, pipebuzone, pipecuronium bromide, pipemidic acid, pipenzolate bromide, pipequaline, piperacetazine, piperacillin, piperamide, piperazine, piperazinedione, piperidolate, piperilate, piperocaine, piperoxan, piperylone, pipobroman, pipoctanone, pipofezine, piposulfan, pipotiazine palmiate, pipoxizine, pipoxolan, pipradimadol, pipradol, pipramadol, pipratecol, piprinhydrinate, piprocurarium iodide, piprofurol, piprozolin, piquindone, piquizil, piracetam, pirandamine, pirarubicin, piraxelate, pirazmonam, pirazolac, pirbenicillin, pirbuterol, pirdonium bromide, pirenoxine, pirenperone, pirenzepine, pirepolol, piretanide, pirfenidone, piribedil, piridicillin, piridocaine, piridoxilate, piridronic acid, pirifibrate, pirindazole, pirinixic acid, pirinixil, piriprost, piriqualone, pirisudanol, piritramide, piritrexim, pirlimycin, pirlindole, pirmagrel, pirmenol, pirnabine, piroctone, pirogliride, piroheptine, pirolate, pirolazamide, piromidic acid, piroxantrone hcl, piroxicam, piroxicam cinnamate, piroxicillin, piroximone, pirozadil, pirprofen, pirquinozol, pirralkonium bromide, pirtenidine, pitenodil, pitofenone, pituxate, pivampicillin, pivenfrine, pivopril, pivoxazepam, pizotyline, plafibride, plaunotol, pleuromulin, plicamycin, podilfen, podophylloxoxin, poldine methylsulfate, polidocanol, ploymyxin, polythiazide, ponalrestat, ponfibrate, porfiromycin, poskine, potassium guaiacolsulfonate, potassium nitrazepate, potassium sodium tartrate, potassium sorbate, potassium thiocyanate, practolol, prajmalium, pralidoxime chloride, pramipexole, pramiracetam, pramiverine, pramoxime, prampine, pranolium chloride, pranoprofen, pranosal, prasterone, pravastatin, praxadine, prazepam, prazepine, praziquantel, prazitone, prazocillin, prazosin, preclamol, prednazate, prednazoline, prednicarbate, prednimustine, prednisolamate, prednisolone, prednisolone acetate, prednisolone hemisuccinate, prednisolone phosphate, prednisolone steaglate, prednisolone tebutate, prednisone, prednival, prednylidene, prefenamate, pregnenolone, pregnenolone succinate, premazepam, prenalterol, prenisteine, prenoverine, prenoxdiazine, prenylamine, pretamazium iodide, pretiadil, pribecaine, pridefine, prideperone, pridinol, prifelone, prifinium bromide, prifuroline, prilocaine, primaperone, primaquine, primidolol, primidone, primycin, prinomide, pristinamycin, prizidilol, proadifen, probarbital, probenecid, probicromil, probucol, procainamide, procaine, procarbazine, procaterol, prochlorperazine, procinolol, procinonide, proclonol, procodazole, procyclidine, procymate, prodeconium bromide, prodilidine, prodipine, prodolic acid, profadol, profexalone, proflavine, proflazepam, progabide, progesterone, proglumetacin, proglumide, proheptazine, proligestone, proline, prolintane, prolonium iodide, promazine, promegestone, promestriene, promethazine, promolate, promoxolane, pronetalol, propacetamol, propafenone, propamidine, propanidid, propanocaine, propantheline bromide, proparacaine, propatyl nitrate, propazolamide, propendiazole, propentofylline, propenzolate, properidine, propetamide, propetandrol, propicillin, propikacin, propinetidine, propiolactone, propiomazine, propipocaine, propiram, propisergide, propiverine, propizepine, propofol, propoxate, propoxycaine, propoxyphene, propranolol, propyl docetrizoate, propylene glycol, propylene glycol monostearate, propyl gallate, propylhexedrine, propyliodone, propylparaben, propylthiouracil, propyperone, propyphenazone, propyromazine bromide, proquazone, proquinolate, prorenoate potassium, proroxan, proscillaridin, prospidium chloride, prostalene, prosulpride, prosultiamine, proterguride, protheobromine, prothipendyl, prothixene, protiofate, protionamide, protirelin, protizinic acid, protokylol, protoveratine, protriptyline, proxazole, proxibarbal, proxibutene, proxicromil, proxifezone, proxorphan, proxyphylline, prozapine, pseudoephedrine, psilocybine, pumiteba, puromycin, pyrabrom, pyran copolymer, pyrantel, pyrathiazine, pyrazinamide, pyrazofurin, pyricarbate, pyridarone, pyridofylline, pyridostigmine bromide, pyridoxine, pyrilamine, pyrimethamine, pyrimitate, pyrinoline, pyrithione zinc, pyrithyldione, pyritidium bromide, pyritinol, pyronine, pyrophenindane, pyrovalerone, pyroxamine, pyrrobutamine, pyrrocaine, pyrroliphene, pyrrolnitrin, pyrvinium chloride, pytamine, quadazocine, quadrosilan, quatacaine, quazepam, quazinone, quazodine, quazolast, quifenadine, quillifoline, quinacainol, quinacillin, quinacrine, quinaldine blue, quinapril, quinaprilat, quinazosin, quinbolone, quincarbate, quindecamine, quindonium bromide, quindoxin, quinestradol, quinestrol, quinethazone, quinetolate, quinezamide, quinfamide, quingestanol acetate, quingestrone, quindine, quinine, quinocide, quinpirole, quinterenol, quintiofos, quinuclium bromide, quinupramine, quipazine, quisultazine, racefemine, racemethionine, racemethorphan, racemetirosine, raclopride, ractopamine, rafoxanide, ralitoline, raloxifene, ramciclane, ramefenazone, ramipril, ramiprilat, ramixotidine, ramnodignin, ranimustine, ranimycin, ranitidine, ranolazine, rathyronine, razinodil, razobazam, razoxane, reboxetine, recainam, reclazepam, relomycin, remoxipride, renanolone, rentiapril, repirinast, repromicin, reproterol, recimetol, rescinnamine, reserpine, resorantel, resorcinol, resorcinol monoacetate, retelliptine, retinol, revenast, ribavirin, riboflavin, riboflavin 5xe2x80x2-phosphate, riboprine, ribostamycin, ridazolol, ridiflone, rifabutin, rifamide, rifampin, rifamycin, rifapentine, rifaximin, rilapine, rilmazafone, rilmenidine, rilopirox, rilozarone, rimantadine, rimazolium metilsulfate, rimcazole, rimexolone, rimiterol, rimoprogin, riodipine, rioprostil, ripazepam, risocaine, risperidone, ristianol, ristocetin, ritanserin, ritiometan, ritodrine, ritropirronium bromide, ritrosulfan, robenidine, rocastine, rociverine, rodocaine, rodorubicin, rofelodine, roflurante, rokitamycin, roletamide, rolgamidine, rolicyclidine, rolicyprine, rolipram, rolitetracycline, rolodine, rolziracetam, romifenone, romifidine, ronactolol, ronidazole, ronifibrate, ronipamil, ronnel, ropitoin, ropivacaine, ropizine, roquinimex, rosaprostol, rosaramicin, rosaramicin butyrate, rosaramicin propionate, rosoxacin, rosterolone, rotamicillin, rotoxamine, rotraxate, roxarsone, roxatidine acetate, roxibolone, roxindole, roxithromycin, roxolonium metilsulfate, roxoperone, rufloxacin, rutamycin, rutin, ruvazone, sabeluzole, saccharin, salacetamide, salafibrate, salantel, salazodine, salazossulfadimedine, salazosulfamide, salazosulfathiazole, salethamide, salfluverine, salicin, salicyl alcohol, salicylamide, salicylanilide, salicylic acid, salinazid, salinomycin, salmefanol, salmeterol, salmisteine, salprotoside, salsalate, salverine, sancycline, sangivamycin, saperconazole, sarcolysin, sarmazenil, sarmoxicillin, sarpicillin, saterinone, satranidazole, savoxepin, scarlet red, scopafungin, scopolamine, seclazone, secnidazole, secobarbital, secoverine, securinine, sedecamycin, seganserin, seglitide, selegiline, selenium sulfide, selprazine, sematilide, semustine, sepazonium chloride, seperidol, sequifenadine, serfibrate, sergolexole, serine, sermetacin, serotonin, sertaconazole, sertraline, setastine, setazindol, setiptiline, setoperone, sevitropium mesilate, sevoflurane, sevopramide, siagoside, sibutramine, siccanin, silandrone, silibinin, silicristin, silidianin, silver sulfadiazine, simetride, simfibrate, simtrazene, simvastatin, sinefungin, sintropium bromide, sisomicin, sitalidone, sitofibrate, sitogluside, sodium benzoate, sodium dibunate, sodium ethasulfate, sodium formaldehyde sulfoxylate, sodium gentisate, sodium gualenate, sodium nitrite, sodium nitroprusside, sodium oxybate, sodium phenylacetate, sodium picofosfate, sodium picosulfate, sodium propionate, sodium stibocaptate, sodium stibogluconate, sodium tetradecyl sulfate, sodium thiosulfate, sofalcone, solasulfone, solpecainol, solypertine, somantadine, sopitazine, sopromidine, soquinolol, sorbic acid, sorbinicate, sorbinil, sorbitan monolaurate, sorbitan monooleate, sorbitan monopalmitate, sorbitan monostearate, sorbitan trioleate, sorbitan tristearate, sorbitol, sorndipine, sotalol, soterenol, spaglumic acid, sparfosic acid, sparsomycin, sparteine, spectinomycin, spiclamine, spiclomazine, spiperone, spiradoline, spiramide, spiramycin, spirapril, spiraprilat, spirendolol, spirgetine, spirilene, spirofylline, spirogermanium, spiromustine, spironolactone, spiroplatin, spirorenone, spirotriazine, spiroxasone, spiroxatrine, spiroxepin, spizofurone, stallimycin, stanolone, stanzolol, stearic acid, stearyl alcohol, stearylsulfamide, steffimycin, stenbolone acetate, stepronin, stercuronium iodide, stevaladil, stibamine glucoside, stibophen, stilbamidine, stilbazium iodide, stilonium iodide, stirimazole, stiripentol, stirocainide, stirifos, streptomycin, streptonicozid, streptonigrin, streptovarycin, streptozocin, strinoline, strychnine, styramate, subathizone, subendazole, succimer, succinylcholine chloride, succinylsulfathiazole, succisulfone, suclofenide, sucralfate, sucrose octaacetate, sudexanox, sudoxicam, sufentanil, sufosfamide, sufotidine, sulazepam, sulbactam, sulbactam pivoxil, sulbenicillin, sulbenox, sulbentine, sulbutiamine, sulclamide, sulconazole, sulfabenz, sulfabenzamide, sulfacarbamide, sulfacecole, sulfacetamide, sulfachlorpyridazine, sulfachrysoidine, sulfaclomide, sulfaclorazole, sulfaclozine, sulfacytine, sulfadiazine, sulfadicramide, sulfadimethoxine, sulfadoxine, sulfaethidole, sulfaguandide, sulfaguanole, sulfalene, sulfaloxic acid, sulfamazone, sulfamerazine, sulfameter, sulfamethazine, sulfamethizole, sulfamethoxazole, sulfamethoxypyridazine, sulfamethoxypyridazine acetyl, sulfametomidine, sulfametrole, sulfamonomethoxine, sulfamoxole, sulfanil amide, sulfanitran, sulfaperin, sulfaphenazole, sulfaproxyline, sulfapyridine, sulfaquinoxaline, sulfarsphenamine, sulfasalazine, sulfasomizole, sulfasuccinamide, sulfasymazine, sulfathiazole, sulfathiourea, sulfatolamide, sulfatroxazole, sulfatrozole, sulfazamet, sulfinalol, sulfinpyrazone, sulfiram, sulfisomidine, sulfisoxazole, sulfisoxazole, sulfobromophthalein, sulfonethylmethane, sulfonmethane, sulfonterol, sulforidazine, sulfoxone sodium, sulicrinat, sulindac, sulisatin, sulisobenzone, sulmarin, sulmazole, sulmepride, sulinidazole, sulocarbilate, suloctidil, sulosemide, sulotroban, suloxifen, sulpiride, sulprosal, sulprostone, sultamicillin, sulthiame, sultopride, sultosilic acid, sultroponium, sulverapride, sumacetamol, sumatriptan, sumetizide, sunagrel, suncillin, supidimide, suproclone, suprofen, suramin, suricainide, suriclone, suxemerid, suxethonium chloride, suxibuzone, symclosene, symetine, synephrine, syrisingopine, taclamine, tacrine, taglutimide, talampicillin, talastine, talbutal, taleranol, talinolol, talipexole, talisomycin, talmetacin, talmetoprim, talniflumate, talopram, talosalate, taloximine, talsupram, taltrimide, tameridone, tameticillin, tametraline, tamitinol, tamoxipen, tampramine, tandamine, taprostene, tartaric acid, tasuldine, taurocholic acid, taurolidine, tauromustine, tauroselcholic acid, taurultam, taxol, tazadolene, tazanolast, tazaburate, tazeprofen, tazifylline, taziprinone, tazolol, tebatizole, tebuquine, teclothiazide, teclozan, tedisamil, tefazoline, tefenperate, tefludazine, teflurane, teflutixol, tegafur, telenzepine, temafloxacin, temarotene, temazepam, temefos, temelastine, temocillin, temodox, temozolomide, temurtide, tenamfetamine, tenilapine, teniloxazine, tenilsetam, teniposide, tenocyclidine, tenonitrozole, tenoxicam, tenylidone, teopranitol, teoprolol, tepirindole, tepoxalin, terazosin, terbinafine, terbucromil, terbufibrol, terbuficin, terbuprol, terbutaline, terciprazine, terconazole, terfenadine, terfluranol, terguride, terizidone, ternidazole, terodiline, terofenamate, teroxalene, teroxirone, terpin hydrate, tertatolol, tesicam, tesimide, testolactone, testosterone, testosterone cypionate, testosterone enanthate, testosterone ketolaurate, testosterone phenylacetate, testosterone propionate, tetrabarbital, tetrabenazine, tetracaine, tetrachloroethylene, tetracycline, tetradonium bromide, tetraethylammonium chloride, tetrahydrozoline, tetramethrin, tetramisole, tetrandrine, tetrantoin, tetrazepam, tetriprofen, tetronasin 5930, tetroquinone, tetroxoprim, tetrydamine, texacromil, thalicarpine, thalidomide, thebacon, thebaine, thenalidine, thenium closylate, thenyldiamine, theobromine, theodrenaline, theofibrate, theophylline, thiabendazole, thiacetarsamide, thialbarbital, thiambutosine, thiamine, thiamiprine, thiamphenicol, thiamylal, thiazesim, thiazinamium chloride, thiazolsulfone, thiethyperazine, thihexinol methylbromide, thimerfonate, thimerosal, thiocarbanidin, thiocarzolamide, thiocolchioside, thiofuradene, thioguanine, thioguanine alpha-deoxyriboside, thioguanine beta-deoxyriboside, thioguanosine, thiohexamide, thioinosine, thiopental, thiopropazate, thioproperazine, thioridazine, thiosalan, thiotepa, thiotetrabarbital, thiothixene, thiouracil, thiphenamil, thiphencillin, thiram, thonzonium bromide, thonzylamine, thozalinone, threonine, thymidine, thymol, thymol iodide, thymopentin, thyromedan, thyropropic acid, tiacrilast, tiadenol, tiafibrate, tiamenidine, tiametonium iodide, tiamulin, tianafac, tianeptine, tiapamil, tiapirinol, tiapride, tiaprofenic acid, tiaprost, tiaramide, tiazofurin, tiazuril, tibalosin, tibenalast sodium, tibenzate, tibezonium iodide, tibolone, tibric acid, tibrofan, tic-mustard, ticabesone propionate, ticarbodine, ticarcillin, ticarcillin cresyl, ticlatone, ticlopidine, ticrynafen, tidiacic, tiemoium iodide, tienocarbine, tienopramine, tienoxolol, tifemoxone, tiflamizole, tiflorex, tifluadom, tiflucarbine, tiformin, tifurac, tigemonam, tigestol, tigloidine, tilbroquinol, tiletamine, tilidine, tiliquinol, tilisolol, tilmicosin, tilomisole, tilorone, tilozepine, tilsuprost, timefurone, timegadine, timelotem, timepidium bromide, timiperone, timobesone acetate, timofibrate, timolol, timonacic, timoprazole, tinabinol, tinazoline, tinidazole, tinisulpride, tinofedrine, tinoridine, tiocarlide, tioclomarol, tioconazole, tioctilate, tiodazosin, tiodonium chloride, tiomergine, tiomesterone, tioperidone, tiopinac, tiopronin, tiopropamine, tiospirone, tiotidine, tioxacin, tioxamast, tioxaprofen, tioxidazole, tioxolone, tipentosin, tipepidine, tipetropium bromide, tipindole, tipredane, tiprenolol, tiprinast, tipropidil, tiprostanide, tiprotimod, tiquinamide, tiquizium bromide, tiratricol, tiropramide, tisocromide, tisopurine, tisoquone, tivandizole, tixadil, tixanox, tixocortol pivalate, tizabrin, tianidine, tizolemide, tizoprolic acid, tobramycin, tobuterol, tocainide, tocamphyl, tocofenoxate, tocofibrate, tocophersolan, todralazine, tofenacin, tofetridine, tofisoline, tofisopam, tolamolol, tolazamide, tolazoline, tolboxane, tolbutamide, tolciclate, toldimfos, tolfamide, tolfenamic acid, tolgabide, tolimidone, tolindate, toliodium chloride, toliprolol, tolmesoxide, tolmetin, tolnaftate, tolnapersine, tolnidamine, toloconium metilsulfate, tolonidine, tolonium chloride, toloxatone, toloxychlorinol, tolpadol, tolpentamide, tolperisone, toliprazole, tolpronine, tolpropamine, tolpyrramide, tolquinzole, tolrestat, toltrazuril, tolufazepam, tolycaine, tomelukast, tomoglumide, tomoxetine, tomoxiprole, tonazocine, topiramate, toprilidine, tonazocine, topiramate, toprilidine, topterone, toquizine, torasemide, toebafylline, toremifene, tosifen, tosufloxacin, tosulur, toyocamycin, toyomycin, traboxepine, tracazolate, tralonide, tramadol, tramazoline, trandolapril, tranexamic acid, tranilast, transcainide, trantelinium bromide, tranylcypromine, trapencaine, trapidil, traxanox, trazilitine, trazium esilate, trazodone, trazolopride, trebenzomine, trecadrine, treloxinate, trenbolone acetate, trengestone, trenizine, trosulfan, trepibutone, trepipam, trepirium iodide, treptilamine, trequensin, trestolone acetate, trethinium tosilate, trethocanoic acid, tretinoin, tretoquinol, triacetin, triafungin, triamcinolone, triamcinolone acetonide, triamcinolone acetonide-phosphate, triamcinolone benetonide, triamcinolone diacetate, triamcinolone furetonide, triamcinolone hexacetonide, triampyzine, triamterene, triazinate, triaziquone, triazolam, tribendilol, tribenoside, tribromoethanol, tribromsalan, tribuzone, triacetamide, trichlormethiazide, trichlormethine, trichloroacetic acid, trichloroethylene, tricribine phosphate, triclabendazole, triclacetamol, triclazate, triclobisonicum chloride, triclocarban, triclodazol, triclofenol, piperazine, triclofos, triclofylline, triclonide, triclosan, tricyclamol chloride, tridihexethyl chloride, trientine, triethylenemelamine, triethylenephosphoramide, trifenagrel, trifezolac, triflocin, triflubazam, triflumidate, trifluomeprazine, trifluoperazine, trifluperidol, triflupromazine, trifluridine, triflusal, trigevolol, trihexyphenidyl, triletide, trilostane, trimazosin, trimebutine, trimecaine, trimedoxime bromide, trimeperidine, trimeprazine, trimetazidine, trimethadione, trimethamide, trimethaphan camsylate, trimethidinium methosulfate, trimethobenzamide, trimethoprim, trimetozine, trimetrexate, trimexiline, trimipramine, trimoprostil, trimoxamine, trioxifene, trioxsalen, tripamide, triparanol, tripelennamine, tripotassium dicitratobismuthate, triprolidine, tritiozine, tritoqualine, trityl cysteine, trixolane, trizoxime, trocimine, troclosene potassium, trofosfamide, troleandomycin, trolnitrate, tromantadine, tromethamine, tropabazate, tropanserin, tropapride, tropatepine, tropenziline bromide, tropicamide, tropigline, tropiprine, tropodifene, trospectomycin, trospium chloride, troxerutin, troxipide, troxolamide, troxonium tosilate, troxypyrrolium tosilate, troxypyrrolium tosilate, truxicurium iodide, truxipicurium iodide, tryparsamide, tryptophan, tryptophane mustard, tuaminoheptane, tubercidine, tubocurarine chloride, tubulozole, tuclazepam, tulobutrol, tuvatidine, tybamate, tylocrebin, tylosin, tyramine, tyropanic acid, tyrosine, ubenimex, ubidecarenone, ubisindine, ufenamate, ufiprazole, uldazepam, ulobetasol, undecoylium chloride, undecyclenic acid, uracil mustard, urapidil, urea, uredepa, uredofos, urefibrate, urethane, uridine, ursodeoxycholic acid, ursucholic acid, vadocaine, valconazole, valdetamide, valdipromide, valine, valnoctamide, valofane, valperinol, valproate pivoxil, valproic acid, valpromide, valtrate, vancomycin hcl, vaneprim, vanillin, vanitolide, vanyldisulfamide, vapiprost, vecuronium bromide, velnacrine maleate, venlafaxine, veradoline, veralipride, verapamil, verazide, verilopam, verofylline, vesnarinone, vetrabutine, vidarabine, vidarabine phophate, vigabatrin, viloxazine, viminol, vinbarbital, vinblastine, vinburnine, vincamine, vincanol, vincantril, vincofos, vinconate, vincristine, vindrburnol, vindesine, vindepidine, vinformide, vinglycinate, vinorelbine, vinpocetine, vinpoline, vinrosidine, vintiamol, vintriptol, vinylbital, vinylether, vinzolidine, viomycin, viprostol, viqualine, viquidil, virginiamycin factors, viroxime, visnadine, visnafylline, vitamine, volazocine, warfarin, xamoterol, xanoxic acid, xanthinol niacinate, xanthiol, xantifibrate, xantocillin, xenalipin, xenazoic acid, xenbucin, xenipentone, xenthiorate, xenygloxal, xenyhexenic acid, xenytropium bromide, xibenolol, xibornol, xilobam, ximoprofen, xinidamine, xinomiline, xipamide, xipranolol, xorphanol, xylamidine, xylazine, xylocoumarol, xylometazoline, xyloxemine, yohimbic acid, zabicipril, zacopride, zafuleptine, zaltidine, zapizolam, zaprinast, zardaverine, zenazocine mesylate, zepastine, zeranol, zetidoline, zidapamide, zidometacin, zidovudine, zilantel, zimeldine, zimidoben, zinc acetate, zinc phenolsulfonate, zinc undecylenate, zindotrine, zindoxifene, zinoconazole, zinterol, zinviroxime, zipeprol, zocainone, zofenopril, zoficonazole, zolamine, zolazepam, zolenzepine, zolertine, zolimidine, zoliprofen, zoloperone, zolpidem, zomebazam, zomepirac, zometapine, zonisamide, zopiclone, zorubicin, zotepine, zoxazolamine, zuclomiphene, zuclophenthixol, zylofuramine.
The following non-limitative examples serve to illustrate the concept of multiple receptor specificity. Other combinations of vectors, spacers and reporters and conjugation technologies leading to multiple vector incorporation are also considered relevant to this invention. Confirmation of the microparticulate nature of products is performed using microscopy as described in WO-A-9607434. Ultrasonic transmission measurements may be made using a broadband transducer to indicate suspensions of products giving an increased sound beam attenuation compared to a standard. Flow cytometric analysis of products can be used to confirm attachment of antibodies thereto. The ability of targeted agents to bind specifically to cells expressing a target may be studied by microscopy and/or using a flow chamber containing immobilised cells, for example employing a population of cells expressing the target structure and a further population of cells not expressing the target. Radioactive, fluorescent or enzyme-labelled streptavidin/avidin may be used to analyse biotin attachment.